diff --git a/src/__tests__/helpers/prime-locales.ts b/src/__tests__/helpers/prime-locales.ts
new file mode 100644
index 000000000..669d9196f
--- /dev/null
+++ b/src/__tests__/helpers/prime-locales.ts
@@ -0,0 +1,25 @@
+/**
+ * Prime client-side message catalogs beyond EN for one test file.
+ *
+ * `vitest.setup.ts` seeds only the EN catalog, because every catalog is
+ * several hundred kilobytes and the setup file runs once per test file. A
+ * test that renders `I18nProvider` in another locale — usually through the
+ * synchronous `renderToStaticMarkup`, which cannot wait for the dynamic
+ * import a locale switch would trigger — calls this at module scope:
+ *
+ *   primeLocales("de");
+ *   primeLocales(...locales); // every locale the app ships
+ *
+ * It registers a file-level `beforeAll` that loads each catalog through the
+ * production loader, so the cache holds exactly what a locale switch in the
+ * app would put there.
+ */
+import { beforeAll } from "vitest";
+import type { Locale } from "@/lib/i18n/config";
+import { loadMessages } from "@/lib/i18n/load-locale";
+
+export function primeLocales(...wanted: readonly Locale[]): void {
+  beforeAll(async () => {
+    await Promise.all(wanted.map((locale) => loadMessages(locale)));
+  });
+}
diff --git a/src/app/achievements/__tests__/page.test.tsx b/src/app/achievements/__tests__/page.test.tsx
index 5f11c7a5b..8cdec5cf2 100644
--- a/src/app/achievements/__tests__/page.test.tsx
+++ b/src/app/achievements/__tests__/page.test.tsx
@@ -166,6 +166,9 @@ vi.mock("@/lib/queries/use-achievements-query", () => ({
 }));
 
 import AchievementsPage, { groupByCategory } from "../page";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/admin/__tests__/backup-restore-status.test.tsx b/src/components/admin/__tests__/backup-restore-status.test.tsx
index 94b604c10..d29ae2964 100644
--- a/src/components/admin/__tests__/backup-restore-status.test.tsx
+++ b/src/components/admin/__tests__/backup-restore-status.test.tsx
@@ -27,6 +27,9 @@ import {
   visibleRestoreJobs,
 } from "@/components/admin/backup-restore-status";
 import type { BackupRestoreJobView } from "@/lib/jobs/backup-restore";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 vi.mock("next/navigation", () => ({
   useRouter: () => ({ push: vi.fn(), replace: vi.fn() }),
diff --git a/src/components/admin/__tests__/backups-restore-refusal-notice.test.tsx b/src/components/admin/__tests__/backups-restore-refusal-notice.test.tsx
index 0553d6859..f85d99c02 100644
--- a/src/components/admin/__tests__/backups-restore-refusal-notice.test.tsx
+++ b/src/components/admin/__tests__/backups-restore-refusal-notice.test.tsx
@@ -31,6 +31,9 @@ import {
   missingSectionsOf,
 } from "@/components/admin/backups-section";
 import type { MissingBackupSection } from "@/lib/export/restore-skips";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 vi.mock("next/navigation", () => ({
   useRouter: () => ({ push: vi.fn(), replace: vi.fn() }),
diff --git a/src/components/admin/__tests__/backups-restore-skip-report.test.tsx b/src/components/admin/__tests__/backups-restore-skip-report.test.tsx
index 5a23df5af..e01f9353c 100644
--- a/src/components/admin/__tests__/backups-restore-skip-report.test.tsx
+++ b/src/components/admin/__tests__/backups-restore-skip-report.test.tsx
@@ -24,6 +24,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { RestoreSkipReport } from "@/components/admin/backups-section";
 import type { RestoreSkipSummary } from "@/lib/export/restore-skips";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 vi.mock("next/navigation", () => ({
   useRouter: () => ({ push: vi.fn(), replace: vi.fn() }),
diff --git a/src/components/admin/__tests__/backups-section-empty.test.tsx b/src/components/admin/__tests__/backups-section-empty.test.tsx
index 85e81600d..14211f4bc 100644
--- a/src/components/admin/__tests__/backups-section-empty.test.tsx
+++ b/src/components/admin/__tests__/backups-section-empty.test.tsx
@@ -83,6 +83,9 @@ vi.mock("@/hooks/use-auth", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { BackupsSection } from "../backups-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   mocks.queryData = {
diff --git a/src/components/admin/__tests__/invite-tokens-section.test.tsx b/src/components/admin/__tests__/invite-tokens-section.test.tsx
index 3b76578ed..2f1b59f4e 100644
--- a/src/components/admin/__tests__/invite-tokens-section.test.tsx
+++ b/src/components/admin/__tests__/invite-tokens-section.test.tsx
@@ -21,6 +21,9 @@ import {
   clampMaxUses,
 } from "@/components/admin/invite-tokens-section";
 import { queryKeys } from "@/lib/query-keys";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const FUTURE = new Date(Date.now() + 7 * 86_400_000).toISOString();
 const PAST = new Date(Date.now() - 86_400_000).toISOString();
diff --git a/src/components/admin/__tests__/key-backup-card.test.tsx b/src/components/admin/__tests__/key-backup-card.test.tsx
index fc5163141..0ddc67a44 100644
--- a/src/components/admin/__tests__/key-backup-card.test.tsx
+++ b/src/components/admin/__tests__/key-backup-card.test.tsx
@@ -19,6 +19,9 @@ import { queryKeys } from "@/lib/query-keys";
 import { KeyBackupCard } from "@/components/admin/key-backup-card";
 import { KeyBackupBanner } from "@/components/dashboard/key-backup-banner";
 import type { KeyBackupStatus } from "@/components/admin/use-key-backup-status";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 vi.mock("next/navigation", () => ({
   useRouter: () => ({ push: vi.fn(), replace: vi.fn() }),
diff --git a/src/components/admin/__tests__/pulse-day-mean-card.test.tsx b/src/components/admin/__tests__/pulse-day-mean-card.test.tsx
index 317901ea6..d63ba45ac 100644
--- a/src/components/admin/__tests__/pulse-day-mean-card.test.tsx
+++ b/src/components/admin/__tests__/pulse-day-mean-card.test.tsx
@@ -16,6 +16,9 @@ import { PulseDayMeanCard } from "@/components/admin/pulse-day-mean-card";
 import { I18nProvider } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
 import type { PulseDayMeanStatus } from "@/lib/validations/pulse-day-mean";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const RESULT = {
   accounts: 2,
diff --git a/src/components/auth/__tests__/insecure-transport-banner.test.tsx b/src/components/auth/__tests__/insecure-transport-banner.test.tsx
index 4446df712..61cea7fea 100644
--- a/src/components/auth/__tests__/insecure-transport-banner.test.tsx
+++ b/src/components/auth/__tests__/insecure-transport-banner.test.tsx
@@ -9,6 +9,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { InsecureTransportBanner } from "@/components/auth/insecure-transport-banner";
 import type { TransportVerdict } from "@/lib/auth/client-transport";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(verdict: TransportVerdict, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/charts/__tests__/chart-data-table.test.tsx b/src/components/charts/__tests__/chart-data-table.test.tsx
index 507010898..8eac4fd3c 100644
--- a/src/components/charts/__tests__/chart-data-table.test.tsx
+++ b/src/components/charts/__tests__/chart-data-table.test.tsx
@@ -7,6 +7,9 @@ import {
   type ChartDataTableProps,
   type ChartTablePoint,
 } from "../chart-data-table";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode) {
   return renderToStaticMarkup(
diff --git a/src/components/charts/__tests__/chart-overlay-controls.test.tsx b/src/components/charts/__tests__/chart-overlay-controls.test.tsx
index 000c158f5..9fa0f9d9c 100644
--- a/src/components/charts/__tests__/chart-overlay-controls.test.tsx
+++ b/src/components/charts/__tests__/chart-overlay-controls.test.tsx
@@ -2,6 +2,9 @@ import { describe, it, expect, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import type { AccountAccess } from "@/lib/sharing/account-access-view";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const OWNER = {
   accountId: "acct-owner",
diff --git a/src/components/charts/__tests__/trend-card-7d-trend.test.tsx b/src/components/charts/__tests__/trend-card-7d-trend.test.tsx
index 2622c9a9c..133332514 100644
--- a/src/components/charts/__tests__/trend-card-7d-trend.test.tsx
+++ b/src/components/charts/__tests__/trend-card-7d-trend.test.tsx
@@ -4,6 +4,9 @@ import { Activity, Smile } from "lucide-react";
 
 import { TrendCard } from "../trend-card";
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.15 Fix 4 — "7-Tage-Schnitt" → "7-Tage-Trend".
diff --git a/src/components/charts/__tests__/trend-card-stale-days.test.tsx b/src/components/charts/__tests__/trend-card-stale-days.test.tsx
index 72fde7852..2f068072b 100644
--- a/src/components/charts/__tests__/trend-card-stale-days.test.tsx
+++ b/src/components/charts/__tests__/trend-card-stale-days.test.tsx
@@ -4,6 +4,9 @@ import { Activity } from "lucide-react";
 
 import { TrendCard } from "../trend-card";
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.34 IW-B — pin the bucket-aware stale-hint copy on `<TrendCard>`.
diff --git a/src/components/charts/__tests__/trend-hint.test.tsx b/src/components/charts/__tests__/trend-hint.test.tsx
index 9d677dedf..724037533 100644
--- a/src/components/charts/__tests__/trend-hint.test.tsx
+++ b/src/components/charts/__tests__/trend-hint.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { TrendHint } from "../trend-hint";
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/cycle/__tests__/custom-symptom-icon-picker.test.tsx b/src/components/cycle/__tests__/custom-symptom-icon-picker.test.tsx
index e828dc7cb..7fc103522 100644
--- a/src/components/cycle/__tests__/custom-symptom-icon-picker.test.tsx
+++ b/src/components/cycle/__tests__/custom-symptom-icon-picker.test.tsx
@@ -35,6 +35,9 @@ vi.mock("../use-cycle", async (importOriginal) => ({
 import { CUSTOM_SYMPTOM_ICON_ALLOWLIST } from "@/lib/cycle/custom-symptoms-shared";
 import { I18nProvider } from "@/lib/i18n/context";
 import { AddSymptomChip } from "../log-day-sheet";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 describe("cycle custom-symptom icon picker", () => {
   it("has 44 px targets on a phone and translated icon names", () => {
diff --git a/src/components/daily/__tests__/today-hero.test.tsx b/src/components/daily/__tests__/today-hero.test.tsx
index 7e58ad751..f3cecf42d 100644
--- a/src/components/daily/__tests__/today-hero.test.tsx
+++ b/src/components/daily/__tests__/today-hero.test.tsx
@@ -9,6 +9,9 @@ import type { PriorityItem } from "@/lib/daily/priority-item";
 import type { TodayFact } from "@/lib/daily/today-overview";
 import { SCORE_VERSION } from "@/lib/analytics/score/types";
 import { DIGEST_AI_AVAILABLE } from "@/__tests__/helpers/ai-capability-fixtures";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 // The hero now wires the coach check-in card's keep / let-go taps through
 // `useCoachCheckinAction`, so it needs a QueryClient in the tree.
diff --git a/src/components/dashboard/__tests__/dashboard-header.test.tsx b/src/components/dashboard/__tests__/dashboard-header.test.tsx
index f5f765e3e..51d4e6297 100644
--- a/src/components/dashboard/__tests__/dashboard-header.test.tsx
+++ b/src/components/dashboard/__tests__/dashboard-header.test.tsx
@@ -48,6 +48,9 @@ import {
   CAPTURE_KIND_ORDER,
   visibleCaptureKinds,
 } from "@/components/layout/capture-picker";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function renderSSR(node: React.ReactElement, locale: "en" | "de" = "de") {
   return renderToStaticMarkup(
diff --git a/src/components/dashboard/__tests__/medication-intake-quick-add.test.tsx b/src/components/dashboard/__tests__/medication-intake-quick-add.test.tsx
index 9b0ca7e92..351fa9641 100644
--- a/src/components/dashboard/__tests__/medication-intake-quick-add.test.tsx
+++ b/src/components/dashboard/__tests__/medication-intake-quick-add.test.tsx
@@ -61,6 +61,9 @@ import {
   type MedicationOption,
 } from "../medication-intake-quick-add";
 import { pickDefaultMedicationId } from "@/lib/medications/default-medication";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function makeMed(
   id: string,
diff --git a/src/components/insights/__tests__/correlation-card.test.tsx b/src/components/insights/__tests__/correlation-card.test.tsx
index c20823f30..31010bf90 100644
--- a/src/components/insights/__tests__/correlation-card.test.tsx
+++ b/src/components/insights/__tests__/correlation-card.test.tsx
@@ -23,6 +23,9 @@ vi.mock("next/dynamic", () => ({
 }));
 
 import { CorrelationCard } from "../correlation-card";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/insights/__tests__/daily-briefing.test.tsx b/src/components/insights/__tests__/daily-briefing.test.tsx
index 80e3039fc..91e00e2a2 100644
--- a/src/components/insights/__tests__/daily-briefing.test.tsx
+++ b/src/components/insights/__tests__/daily-briefing.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { DailyBriefing } from "../daily-briefing";
 import type { DailyBriefing as DailyBriefingPayload } from "@/lib/ai/schema";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 // The updated-at footer reads the profile timezone via `useAuth`; stub it so the
 // SSR render does not reach for a QueryClient the static-markup test omits.
diff --git a/src/components/insights/__tests__/health-score-card.test.tsx b/src/components/insights/__tests__/health-score-card.test.tsx
index 7fc8504d2..f709f6f53 100644
--- a/src/components/insights/__tests__/health-score-card.test.tsx
+++ b/src/components/insights/__tests__/health-score-card.test.tsx
@@ -19,6 +19,9 @@ import {
   pillarObservedText,
   type Translate,
 } from "../health-score-pillar-detail";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 let mockAuthUser: {
   unitPreference: string;
diff --git a/src/components/insights/__tests__/health-score-pillar-detail-bp-basis.test.tsx b/src/components/insights/__tests__/health-score-pillar-detail-bp-basis.test.tsx
index 6c952ca25..13ce5c2ff 100644
--- a/src/components/insights/__tests__/health-score-pillar-detail-bp-basis.test.tsx
+++ b/src/components/insights/__tests__/health-score-pillar-detail-bp-basis.test.tsx
@@ -23,6 +23,9 @@ import {
   pillarDetailLines,
   type Translate,
 } from "../health-score-pillar-detail";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function translator(locale: Locale = "en"): Translate {
   let captured: Translate | null = null;
diff --git a/src/components/insights/__tests__/hero-strip.test.tsx b/src/components/insights/__tests__/hero-strip.test.tsx
index f45599a3d..41898aca4 100644
--- a/src/components/insights/__tests__/hero-strip.test.tsx
+++ b/src/components/insights/__tests__/hero-strip.test.tsx
@@ -9,6 +9,9 @@ import type {
   ScorePillarResult,
 } from "@/lib/analytics/score/types";
 import { SCORE_VERSION } from "@/lib/analytics/score/types";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 // The "generated" freshness line reads the profile timezone via `useAuth`; stub
 // it so the SSR render does not reach for a QueryClient the test omits.
diff --git a/src/components/insights/__tests__/integer-metric-precision-guard.test.tsx b/src/components/insights/__tests__/integer-metric-precision-guard.test.tsx
index 357ad8ff8..1e56b9872 100644
--- a/src/components/insights/__tests__/integer-metric-precision-guard.test.tsx
+++ b/src/components/insights/__tests__/integer-metric-precision-guard.test.tsx
@@ -73,6 +73,9 @@ vi.mock("@tanstack/react-query", async (importOriginal) => {
 
 import { CoachReadStrip } from "../derived/coach-read-strip";
 import InsightsStepsPage from "@/app/insights/steps/page";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "de") {
   const queryClient = new QueryClient({
diff --git a/src/components/insights/__tests__/sleep-stage-stacked-bar.test.tsx b/src/components/insights/__tests__/sleep-stage-stacked-bar.test.tsx
index 6ea7b026f..15be7c3aa 100644
--- a/src/components/insights/__tests__/sleep-stage-stacked-bar.test.tsx
+++ b/src/components/insights/__tests__/sleep-stage-stacked-bar.test.tsx
@@ -12,6 +12,9 @@ import {
   type SleepStageBreakdown,
   type SleepStageNight,
 } from "../sleep-stage-stacked-bar";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.25 W4c / W3f — sleep-stage stacked-bar chart unit tests.
diff --git a/src/components/insights/__tests__/trend-annotation.test.tsx b/src/components/insights/__tests__/trend-annotation.test.tsx
index 649c447d1..affaba2e9 100644
--- a/src/components/insights/__tests__/trend-annotation.test.tsx
+++ b/src/components/insights/__tests__/trend-annotation.test.tsx
@@ -2,6 +2,9 @@ import { describe, it, expect } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { TrendAnnotation } from "../trend-annotation";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.20 phase B3 — single-sentence trend annotation under each
diff --git a/src/components/insights/__tests__/trend-descriptor-caption.test.tsx b/src/components/insights/__tests__/trend-descriptor-caption.test.tsx
index 9b0bdbd09..851236296 100644
--- a/src/components/insights/__tests__/trend-descriptor-caption.test.tsx
+++ b/src/components/insights/__tests__/trend-descriptor-caption.test.tsx
@@ -23,6 +23,9 @@ vi.mock("@/hooks/use-auth", () => ({
 }));
 
 import { TrendDescriptorCaption } from "../trend-annotation";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function seededClient(seed: (client: QueryClient) => void): QueryClient {
   const client = new QueryClient({
diff --git a/src/components/insights/coach-panel/__tests__/coach-drawer-mobile-trays.test.tsx b/src/components/insights/coach-panel/__tests__/coach-drawer-mobile-trays.test.tsx
index da352e3ac..cc264f6ac 100644
--- a/src/components/insights/coach-panel/__tests__/coach-drawer-mobile-trays.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/coach-drawer-mobile-trays.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { CoachDrawerBody } from "../coach-drawer-body";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.20 phase B4 — Coach drawer rail-tray strip.
diff --git a/src/components/insights/coach-panel/__tests__/coach-hero.test.tsx b/src/components/insights/coach-panel/__tests__/coach-hero.test.tsx
index c99ade4de..c6fde0eb0 100644
--- a/src/components/insights/coach-panel/__tests__/coach-hero.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/coach-hero.test.tsx
@@ -4,6 +4,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { CoachHero } from "../coach-hero";
 import { splitProseSegments } from "../streamed-prose";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/insights/coach-panel/__tests__/coach-input.test.tsx b/src/components/insights/coach-panel/__tests__/coach-input.test.tsx
index d6f200bf4..0c514fbda 100644
--- a/src/components/insights/coach-panel/__tests__/coach-input.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/coach-input.test.tsx
@@ -339,6 +339,9 @@ describe("<CoachInput>", () => {
 // textarea's auto-grow effect. Pin its math so the textarea never
 // collapses below a single line or grows past the 6-line ceiling.
 import { computeAutoGrowHeight } from "../coach-input";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 describe("computeAutoGrowHeight", () => {
   it("clamps to the single-line minimum when scrollHeight is empty", () => {
diff --git a/src/components/insights/coach-panel/__tests__/guided-dialog.test.tsx b/src/components/insights/coach-panel/__tests__/guided-dialog.test.tsx
index e79a5c3c1..dc8ce9610 100644
--- a/src/components/insights/coach-panel/__tests__/guided-dialog.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/guided-dialog.test.tsx
@@ -8,6 +8,9 @@ import {
   GuidedSummaryBubble,
 } from "../guided-dialog-bubbles";
 import { GuidedQuestionsCard } from "../guided-questions-card";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.16.5 — markup-level coverage for the guided clarifying-questions
diff --git a/src/components/insights/coach-panel/__tests__/history-rail.test.tsx b/src/components/insights/coach-panel/__tests__/history-rail.test.tsx
index 121e67ccd..91c272f36 100644
--- a/src/components/insights/coach-panel/__tests__/history-rail.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/history-rail.test.tsx
@@ -6,6 +6,9 @@ import { I18nProvider } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
 import { HistoryRail } from "../history-rail";
 import type { CoachConversationsPage } from "@/lib/ai/coach/types";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.20 phase B2b — history-rail render snapshot.
diff --git a/src/components/insights/coach-panel/__tests__/message-thread.test.tsx b/src/components/insights/coach-panel/__tests__/message-thread.test.tsx
index 3ddcfb18c..f03b233ad 100644
--- a/src/components/insights/coach-panel/__tests__/message-thread.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/message-thread.test.tsx
@@ -760,6 +760,9 @@ describe("<MessageThread>", () => {
 // changes can't silently demote the daily-limit / rate-limit copy
 // back to the generic provider-unavailable fallback.
 import { errorCodeToI18nKey } from "../message-thread";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 describe("errorCodeToI18nKey", () => {
   it("maps daily-budget exceedance to the dedicated key", () => {
diff --git a/src/components/insights/coach-panel/__tests__/method-line.test.tsx b/src/components/insights/coach-panel/__tests__/method-line.test.tsx
index 4bad227d3..1b5885887 100644
--- a/src/components/insights/coach-panel/__tests__/method-line.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/method-line.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { CoachMethodLine } from "../method-line";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/insights/coach-panel/__tests__/mobile-rail-tray.test.tsx b/src/components/insights/coach-panel/__tests__/mobile-rail-tray.test.tsx
index 3c1d17d45..cda0b2e62 100644
--- a/src/components/insights/coach-panel/__tests__/mobile-rail-tray.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/mobile-rail-tray.test.tsx
@@ -39,6 +39,9 @@ vi.mock("@/components/ui/sheet", () => ({
 }));
 
 import { MobileRailTray } from "../mobile-rail-tray";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/insights/coach-panel/__tests__/turn-activity.test.tsx b/src/components/insights/coach-panel/__tests__/turn-activity.test.tsx
index 6787b7ae7..2c8257529 100644
--- a/src/components/insights/coach-panel/__tests__/turn-activity.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/turn-activity.test.tsx
@@ -24,6 +24,9 @@ import {
   stepIcon,
   stepLabel,
 } from "../turn-activity";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "pl");
 
 function render(node: React.ReactNode, locale: Locale = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/insights/derived/__tests__/coach-read-strip-same-hours.test.tsx b/src/components/insights/derived/__tests__/coach-read-strip-same-hours.test.tsx
index 2999b1d8d..1667411bd 100644
--- a/src/components/insights/derived/__tests__/coach-read-strip-same-hours.test.tsx
+++ b/src/components/insights/derived/__tests__/coach-read-strip-same-hours.test.tsx
@@ -23,6 +23,9 @@ vi.mock("@/hooks/use-auth", () => ({
 vi.mock("@/hooks/use-mounted", () => ({ useMounted: () => true }));
 
 import { CoachReadStrip } from "../coach-read-strip";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const METRIC = "BLOOD_GLUCOSE";
 
diff --git a/src/components/insights/glucose/__tests__/glucose-clinical-panel.test.tsx b/src/components/insights/glucose/__tests__/glucose-clinical-panel.test.tsx
index bc39ce83f..5367c0650 100644
--- a/src/components/insights/glucose/__tests__/glucose-clinical-panel.test.tsx
+++ b/src/components/insights/glucose/__tests__/glucose-clinical-panel.test.tsx
@@ -6,6 +6,9 @@ import { computeGlucoseClinicalMetrics } from "@/lib/analytics/glucose-metrics";
 import type { DataSummary } from "@/lib/analytics/trends";
 import { GlucoseTirBar } from "../glucose-tir-bar";
 import { GlucoseAdvancedDisclosure } from "../glucose-advanced-disclosure";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /** Minimal valid `DataSummary` — the panel + disclosure only read `count`. */
 function summary(count: number): DataSummary {
diff --git a/src/components/insights/nutrients/__tests__/micronutrients-upper-limit.test.tsx b/src/components/insights/nutrients/__tests__/micronutrients-upper-limit.test.tsx
index 53e25e3cb..ebde65007 100644
--- a/src/components/insights/nutrients/__tests__/micronutrients-upper-limit.test.tsx
+++ b/src/components/insights/nutrients/__tests__/micronutrients-upper-limit.test.tsx
@@ -22,6 +22,9 @@ vi.mock("@/hooks/use-auth", () => ({
 }));
 
 import { MicronutrientsCard } from "../micronutrients-card";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(rows: NutrientOverviewRow[], locale: "en" | "de" = "en") {
   state.rows = rows;
diff --git a/src/components/labs/__tests__/biomarker-aliases.test.tsx b/src/components/labs/__tests__/biomarker-aliases.test.tsx
index faf6b5608..9c94bb33e 100644
--- a/src/components/labs/__tests__/biomarker-aliases.test.tsx
+++ b/src/components/labs/__tests__/biomarker-aliases.test.tsx
@@ -11,6 +11,9 @@ vi.mock("@/hooks/use-record-capabilities", () => ({
 import { BiomarkerAliases } from "../biomarker-aliases";
 import { BiomarkerMergeSheet } from "../biomarker-merge-sheet";
 import type { BiomarkerDto } from "../types";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 vi.mock("@/components/ui/responsive-sheet", () => ({
   ResponsiveSheet: ({
diff --git a/src/components/labs/__tests__/lab-converted-note.test.tsx b/src/components/labs/__tests__/lab-converted-note.test.tsx
index af70a67d7..5ead9e5b0 100644
--- a/src/components/labs/__tests__/lab-converted-note.test.tsx
+++ b/src/components/labs/__tests__/lab-converted-note.test.tsx
@@ -4,6 +4,9 @@ import { describe, expect, it } from "vitest";
 import { I18nProvider } from "@/lib/i18n/context";
 
 import { LabConvertedNote } from "../lab-converted-note";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(
   reading: Parameters<typeof LabConvertedNote>[0]["reading"],
diff --git a/src/components/labs/__tests__/ocr-marker-match.test.tsx b/src/components/labs/__tests__/ocr-marker-match.test.tsx
index 6e89bba6b..846a364c9 100644
--- a/src/components/labs/__tests__/ocr-marker-match.test.tsx
+++ b/src/components/labs/__tests__/ocr-marker-match.test.tsx
@@ -11,6 +11,9 @@ import {
 } from "../ocr-review-types";
 import { toCommitRow } from "../ocr-review-validation";
 import { OcrRowEditor } from "../ocr-row-editor";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const dto: OcrExtractedRowDto = {
   analyte: "Bilirubin ges.",
diff --git a/src/components/labs/__tests__/ocr-review-dialog.test.tsx b/src/components/labs/__tests__/ocr-review-dialog.test.tsx
index 7383165f8..62d1ece19 100644
--- a/src/components/labs/__tests__/ocr-review-dialog.test.tsx
+++ b/src/components/labs/__tests__/ocr-review-dialog.test.tsx
@@ -15,6 +15,9 @@ import {
   OcrReviewDialog,
   unitSkippedAnalytes,
 } from "../ocr-review-dialog";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const hookState = vi.hoisted(() => ({
   extractPending: false,
diff --git a/src/components/labs/__tests__/ocr-row-editor.test.tsx b/src/components/labs/__tests__/ocr-row-editor.test.tsx
index 971170ffb..4c9544922 100644
--- a/src/components/labs/__tests__/ocr-row-editor.test.tsx
+++ b/src/components/labs/__tests__/ocr-row-editor.test.tsx
@@ -5,6 +5,9 @@ import { I18nProvider } from "@/lib/i18n/context";
 
 import type { OcrReviewRow } from "../ocr-review-types";
 import { OcrRowEditor } from "../ocr-row-editor";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const baseRow: OcrReviewRow = {
   key: "LDL-0",
diff --git a/src/components/layout/__tests__/keyboard-shortcuts-dialog.test.tsx b/src/components/layout/__tests__/keyboard-shortcuts-dialog.test.tsx
index ecd79740a..ee621a503 100644
--- a/src/components/layout/__tests__/keyboard-shortcuts-dialog.test.tsx
+++ b/src/components/layout/__tests__/keyboard-shortcuts-dialog.test.tsx
@@ -29,6 +29,9 @@ vi.mock("@/components/ui/responsive-sheet", () => ({
 }));
 
 import { KeyboardShortcutsDialog } from "../keyboard-shortcuts-dialog";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "es", "fr", "it", "pl", "ko", "nl");
 
 const EVERYTHING = {
   navHrefs: ["/", "/medications", "/labs", "/timeline", "/insights", "/coach"],
diff --git a/src/components/measurements/__tests__/duration-read-as.test.tsx b/src/components/measurements/__tests__/duration-read-as.test.tsx
index eb7eb2554..76ee4f647 100644
--- a/src/components/measurements/__tests__/duration-read-as.test.tsx
+++ b/src/components/measurements/__tests__/duration-read-as.test.tsx
@@ -6,6 +6,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { parseDurationEntry } from "@/lib/measurements/parse-duration";
 import { DurationReadAs } from "../duration-read-as";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "ko");
 
 /**
  * The hint under a duration field says how the entry was read, so "7.5",
diff --git a/src/components/measurements/__tests__/measurement-list-filter-select.test.tsx b/src/components/measurements/__tests__/measurement-list-filter-select.test.tsx
index f7ec021bf..b3fefea4f 100644
--- a/src/components/measurements/__tests__/measurement-list-filter-select.test.tsx
+++ b/src/components/measurements/__tests__/measurement-list-filter-select.test.tsx
@@ -63,6 +63,9 @@ vi.mock("@/hooks/use-auth", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { MeasurementList } from "../measurement-list";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/measurements/__tests__/measurement-list-step-grouping.test.tsx b/src/components/measurements/__tests__/measurement-list-step-grouping.test.tsx
index 13ef32e92..5394b2261 100644
--- a/src/components/measurements/__tests__/measurement-list-step-grouping.test.tsx
+++ b/src/components/measurements/__tests__/measurement-list-step-grouping.test.tsx
@@ -64,6 +64,9 @@ vi.mock("@/hooks/use-auth", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { MeasurementList } from "../measurement-list";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/medications/__tests__/add-inventory-dialog.test.tsx b/src/components/medications/__tests__/add-inventory-dialog.test.tsx
index d6861fec3..886895218 100644
--- a/src/components/medications/__tests__/add-inventory-dialog.test.tsx
+++ b/src/components/medications/__tests__/add-inventory-dialog.test.tsx
@@ -16,6 +16,9 @@ import { resolve } from "node:path";
 import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 // The Radix Dialog / Select portal at runtime, so their bodies never
 // materialise in static markup. Collapse the primitives to plain
diff --git a/src/components/medications/__tests__/injection-site-picker.test.tsx b/src/components/medications/__tests__/injection-site-picker.test.tsx
index 5c3b971a7..dce77a99e 100644
--- a/src/components/medications/__tests__/injection-site-picker.test.tsx
+++ b/src/components/medications/__tests__/injection-site-picker.test.tsx
@@ -7,6 +7,9 @@ import {
   INJECTION_SITE_KEYS,
   type InjectionSiteKey,
 } from "@/lib/medications/injection-sites";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.25 W4d-tests — RTL-style coverage for the body-map injection
diff --git a/src/components/medications/__tests__/intake-history-list-v2.test.tsx b/src/components/medications/__tests__/intake-history-list-v2.test.tsx
index f409b3586..3bf35055e 100644
--- a/src/components/medications/__tests__/intake-history-list-v2.test.tsx
+++ b/src/components/medications/__tests__/intake-history-list-v2.test.tsx
@@ -5,6 +5,9 @@ import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 import { I18nProvider } from "@/lib/i18n/context";
 import { IntakeHistoryListV2 } from "@/components/medications/intake-history-list-v2";
 import { queryKeys } from "@/lib/query-keys";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.36 W4a — IntakeHistoryListV2 SSR smoke tests.
diff --git a/src/components/medications/__tests__/inventory-section-actions.test.tsx b/src/components/medications/__tests__/inventory-section-actions.test.tsx
index f691f49c0..c51adb382 100644
--- a/src/components/medications/__tests__/inventory-section-actions.test.tsx
+++ b/src/components/medications/__tests__/inventory-section-actions.test.tsx
@@ -17,6 +17,9 @@ import { describe, expect, it, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const useQueryMock = vi.fn();
 
diff --git a/src/components/medications/__tests__/inventory-section-dates.test.tsx b/src/components/medications/__tests__/inventory-section-dates.test.tsx
index adf6c3dd5..31e8b9b10 100644
--- a/src/components/medications/__tests__/inventory-section-dates.test.tsx
+++ b/src/components/medications/__tests__/inventory-section-dates.test.tsx
@@ -17,6 +17,9 @@ import { describe, expect, it, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 // Now-anchored future expiry (the fixed 2027-06-01 was a fuse: once the
 // calendar passes it, an "expiring later" fixture silently becomes an
diff --git a/src/components/medications/__tests__/inventory-section-summary.test.tsx b/src/components/medications/__tests__/inventory-section-summary.test.tsx
index 9c9fa416b..906e76665 100644
--- a/src/components/medications/__tests__/inventory-section-summary.test.tsx
+++ b/src/components/medications/__tests__/inventory-section-summary.test.tsx
@@ -20,6 +20,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { summariseSupply } from "@/lib/medications/inventory/summary";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const useQueryMock = vi.fn();
 
diff --git a/src/components/medications/__tests__/medication-card-glp1.test.tsx b/src/components/medications/__tests__/medication-card-glp1.test.tsx
index 2ee9567b7..9cddeffc1 100644
--- a/src/components/medications/__tests__/medication-card-glp1.test.tsx
+++ b/src/components/medications/__tests__/medication-card-glp1.test.tsx
@@ -8,6 +8,9 @@ import {
   type Glp1Medication,
 } from "@/components/medications/glp1-medication-card";
 import { MedicationCard } from "@/components/medications/medication-card";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.25 W4d-tests — RTL-style component coverage for the GLP-1
diff --git a/src/components/medications/__tests__/medication-order-editor.test.tsx b/src/components/medications/__tests__/medication-order-editor.test.tsx
index 55e71c5c8..262d0f7fd 100644
--- a/src/components/medications/__tests__/medication-order-editor.test.tsx
+++ b/src/components/medications/__tests__/medication-order-editor.test.tsx
@@ -20,6 +20,9 @@ import { describe, expect, it, vi } from "vitest";
 import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 vi.mock("@tanstack/react-query", () => ({
   useQueryClient: () => ({}),
diff --git a/src/components/medications/__tests__/side-effects-section.test.tsx b/src/components/medications/__tests__/side-effects-section.test.tsx
index 7737bd290..f5c43705e 100644
--- a/src/components/medications/__tests__/side-effects-section.test.tsx
+++ b/src/components/medications/__tests__/side-effects-section.test.tsx
@@ -40,6 +40,9 @@ vi.mock("@/components/ui/query-error-card", async () => {
 });
 
 import { SideEffectsSection } from "@/components/medications/side-effects-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.25 W19d — SideEffectsSection SSR smoke tests.
diff --git a/src/components/medications/__tests__/take-all-due.test.tsx b/src/components/medications/__tests__/take-all-due.test.tsx
index f6aa792e2..643ae8be7 100644
--- a/src/components/medications/__tests__/take-all-due.test.tsx
+++ b/src/components/medications/__tests__/take-all-due.test.tsx
@@ -14,6 +14,9 @@ import {
   type DueDerivationMedication,
   type DueMedication,
 } from "@/components/medications/take-all-due";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.16.11 (#316) — "take all due at once" coverage.
diff --git a/src/components/medications/__tests__/units-per-dose-field.test.tsx b/src/components/medications/__tests__/units-per-dose-field.test.tsx
index 9a6bfc953..351ae6457 100644
--- a/src/components/medications/__tests__/units-per-dose-field.test.tsx
+++ b/src/components/medications/__tests__/units-per-dose-field.test.tsx
@@ -13,6 +13,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import { summariseSupply } from "@/lib/medications/inventory/summary";
 import { UnitsPerDoseField } from "../units-per-dose-field";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const useQueryMock = vi.fn();
 
diff --git a/src/components/medications/scheduling/__tests__/schedule-history-timeline.test.tsx b/src/components/medications/scheduling/__tests__/schedule-history-timeline.test.tsx
index f212012ae..5bce9f830 100644
--- a/src/components/medications/scheduling/__tests__/schedule-history-timeline.test.tsx
+++ b/src/components/medications/scheduling/__tests__/schedule-history-timeline.test.tsx
@@ -28,6 +28,9 @@ import {
   type ScheduleRevisionRow,
 } from "@/components/medications/scheduling/schedule-history-timeline";
 import { queryKeys } from "@/lib/query-keys";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const MED_ID = "med-1";
 
diff --git a/src/components/mood/__tests__/mood-tag-icon-picker.test.tsx b/src/components/mood/__tests__/mood-tag-icon-picker.test.tsx
index e16ce4265..982fcca10 100644
--- a/src/components/mood/__tests__/mood-tag-icon-picker.test.tsx
+++ b/src/components/mood/__tests__/mood-tag-icon-picker.test.tsx
@@ -15,6 +15,9 @@ import {
 } from "@/lib/mood/icon-catalog";
 import { isMoodTagIconName } from "../mood-tag-icons";
 import { MoodTagIconPicker, filterIconCatalog } from "../mood-tag-icon-picker";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "es", "fr", "it", "pl");
 
 describe("filterIconCatalog", () => {
   it("returns the full drawable catalog for an empty query", () => {
diff --git a/src/components/mood/__tests__/mood-tag-picker-custom.test.tsx b/src/components/mood/__tests__/mood-tag-picker-custom.test.tsx
index 835e99511..4d491b507 100644
--- a/src/components/mood/__tests__/mood-tag-picker-custom.test.tsx
+++ b/src/components/mood/__tests__/mood-tag-picker-custom.test.tsx
@@ -51,6 +51,9 @@ vi.mock("@/hooks/use-auth", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { MoodTagPicker } from "../mood-tag-picker";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const CATALOG = {
   categories: [
diff --git a/src/components/onboarding/__tests__/baseline-fields-rejection-slots.test.tsx b/src/components/onboarding/__tests__/baseline-fields-rejection-slots.test.tsx
index 57aec24f9..43cbc628e 100644
--- a/src/components/onboarding/__tests__/baseline-fields-rejection-slots.test.tsx
+++ b/src/components/onboarding/__tests__/baseline-fields-rejection-slots.test.tsx
@@ -30,6 +30,9 @@ import {
   describeBaselineSaveOutcome,
   putBaselineProfile,
 } from "../baseline-form-utils";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /** A `t` backed by the shipped bundle — no stand-in strings. */
 function translator(locale: "en" | "de") {
diff --git a/src/components/onboarding/__tests__/baseline-form-rejected-fields.test.ts b/src/components/onboarding/__tests__/baseline-form-rejected-fields.test.ts
index 8094ddbe0..aecf162e5 100644
--- a/src/components/onboarding/__tests__/baseline-form-rejected-fields.test.ts
+++ b/src/components/onboarding/__tests__/baseline-form-rejected-fields.test.ts
@@ -19,6 +19,9 @@ import {
   describeBaselineSaveOutcome,
   putBaselineProfile,
 } from "../baseline-form-utils";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /** A `t` backed by the shipped bundle — no stand-in strings. */
 function translator(locale: "en" | "de") {
diff --git a/src/components/onboarding/__tests__/tour.test.tsx b/src/components/onboarding/__tests__/tour.test.tsx
index 9b7ed282b..6f5347f87 100644
--- a/src/components/onboarding/__tests__/tour.test.tsx
+++ b/src/components/onboarding/__tests__/tour.test.tsx
@@ -18,6 +18,9 @@ vi.mock("next/navigation", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { OnboardingTour } from "../tour";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function renderTour(modules?: Record<string, boolean>) {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/advanced-account-delete.test.tsx b/src/components/settings/__tests__/advanced-account-delete.test.tsx
index fa59afecd..6212992d9 100644
--- a/src/components/settings/__tests__/advanced-account-delete.test.tsx
+++ b/src/components/settings/__tests__/advanced-account-delete.test.tsx
@@ -30,6 +30,9 @@ vi.mock("@tanstack/react-query", () => ({
 }));
 
 import { AdvancedSection } from "../advanced-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/ai-section.test.tsx b/src/components/settings/__tests__/ai-section.test.tsx
index c06f2e1ba..bf394bde3 100644
--- a/src/components/settings/__tests__/ai-section.test.tsx
+++ b/src/components/settings/__tests__/ai-section.test.tsx
@@ -126,6 +126,9 @@ vi.mock("@tanstack/react-query", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { AiSection } from "../ai-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/coach-section.test.tsx b/src/components/settings/__tests__/coach-section.test.tsx
index 157b489e1..e2fa7ad86 100644
--- a/src/components/settings/__tests__/coach-section.test.tsx
+++ b/src/components/settings/__tests__/coach-section.test.tsx
@@ -61,6 +61,9 @@ vi.mock("@/hooks/use-auth", () => ({
 import { I18nProvider } from "@/lib/i18n/context";
 import { SettingsSectionFrame } from "./section-frame-harness";
 import { CoachSection } from "../coach-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   // v1.18.6 (W9) — the visible heading lives in the shared frame the route
diff --git a/src/components/settings/__tests__/dashboard-layout-section.test.tsx b/src/components/settings/__tests__/dashboard-layout-section.test.tsx
index e7e48ff62..56693609b 100644
--- a/src/components/settings/__tests__/dashboard-layout-section.test.tsx
+++ b/src/components/settings/__tests__/dashboard-layout-section.test.tsx
@@ -85,6 +85,9 @@ import {
   reorderWidgets,
   setHeroItemKindEnabled,
 } from "../dashboard-layout-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactElement, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/export-section.test.tsx b/src/components/settings/__tests__/export-section.test.tsx
index aaf2fb52b..623abf838 100644
--- a/src/components/settings/__tests__/export-section.test.tsx
+++ b/src/components/settings/__tests__/export-section.test.tsx
@@ -46,6 +46,9 @@ vi.mock("@/hooks/use-auth", () => ({
 import { I18nProvider } from "@/lib/i18n/context";
 import { SettingsSectionFrame } from "./section-frame-harness";
 import { ExportSection } from "../export-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactElement, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/integration-status-pill.test.tsx b/src/components/settings/__tests__/integration-status-pill.test.tsx
index e7d83467e..73444500f 100644
--- a/src/components/settings/__tests__/integration-status-pill.test.tsx
+++ b/src/components/settings/__tests__/integration-status-pill.test.tsx
@@ -21,6 +21,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { IntegrationStatusPill } from "../integration-status-pill";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactNode, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/layout-section.test.tsx b/src/components/settings/__tests__/layout-section.test.tsx
index 68264986a..5b4935d64 100644
--- a/src/components/settings/__tests__/layout-section.test.tsx
+++ b/src/components/settings/__tests__/layout-section.test.tsx
@@ -34,6 +34,9 @@ vi.mock("@/hooks/use-mounted", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { LayoutSection } from "../layout-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(modules?: Record<string, boolean>, locale: "en" | "de" = "en") {
   authRef.modules = modules;
diff --git a/src/components/settings/__tests__/medications-section.test.tsx b/src/components/settings/__tests__/medications-section.test.tsx
index 8704f98e9..ba5cd17f4 100644
--- a/src/components/settings/__tests__/medications-section.test.tsx
+++ b/src/components/settings/__tests__/medications-section.test.tsx
@@ -67,6 +67,9 @@ vi.mock("@/hooks/use-auth", () => ({
 import { I18nProvider } from "@/lib/i18n/context";
 import { SettingsSectionFrame } from "./section-frame-harness";
 import { MedicationsSection } from "../medications-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en"): string {
   // v1.18.6 (W9) — the visible heading (with the historic id) comes from the
diff --git a/src/components/settings/__tests__/mood-section.test.tsx b/src/components/settings/__tests__/mood-section.test.tsx
index 0ded8ad9d..50daf200f 100644
--- a/src/components/settings/__tests__/mood-section.test.tsx
+++ b/src/components/settings/__tests__/mood-section.test.tsx
@@ -133,6 +133,9 @@ vi.mock("@/hooks/use-auth", () => ({
 import { I18nProvider } from "@/lib/i18n/context";
 import { SettingsSectionFrame } from "./section-frame-harness";
 import { MoodSection } from "../mood-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en"): string {
   // v1.18.6 (W9) — the visible heading (with the historic id) comes from the
diff --git a/src/components/settings/__tests__/notification-status-card.test.tsx b/src/components/settings/__tests__/notification-status-card.test.tsx
index a472b5593..c2e23bd43 100644
--- a/src/components/settings/__tests__/notification-status-card.test.tsx
+++ b/src/components/settings/__tests__/notification-status-card.test.tsx
@@ -45,6 +45,9 @@ vi.mock("@/hooks/use-mounted", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { NotificationStatusCard } from "../notification-status-card";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactElement, locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/score-change-notice.test.tsx b/src/components/settings/__tests__/score-change-notice.test.tsx
index 4c50ba780..a326ae2a4 100644
--- a/src/components/settings/__tests__/score-change-notice.test.tsx
+++ b/src/components/settings/__tests__/score-change-notice.test.tsx
@@ -12,6 +12,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 import { I18nProvider } from "@/lib/i18n/context";
 import type { Locale } from "@/lib/i18n/config";
 import { ScoreChangeNotice } from "../score-change-notice";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "es", "fr", "it", "pl");
 
 function render(
   props: {
diff --git a/src/components/settings/__tests__/score-composition-notice.test.tsx b/src/components/settings/__tests__/score-composition-notice.test.tsx
index 178e25a19..206fc612f 100644
--- a/src/components/settings/__tests__/score-composition-notice.test.tsx
+++ b/src/components/settings/__tests__/score-composition-notice.test.tsx
@@ -15,6 +15,9 @@ import { I18nProvider } from "@/lib/i18n/context";
 import type { Locale } from "@/lib/i18n/config";
 import type { ScorePillarId } from "@/lib/analytics/score/types";
 import { ScoreCompositionNotice } from "../score-composition-notice";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "ko");
 
 function render(
   props: { left: ScorePillarId[]; joined: ScorePillarId[] },
diff --git a/src/components/settings/__tests__/score-pillar-row.test.tsx b/src/components/settings/__tests__/score-pillar-row.test.tsx
index 1f73430cc..40e84c6da 100644
--- a/src/components/settings/__tests__/score-pillar-row.test.tsx
+++ b/src/components/settings/__tests__/score-pillar-row.test.tsx
@@ -12,6 +12,9 @@ import { I18nProvider } from "@/lib/i18n/context";
 import type { Locale } from "@/lib/i18n/config";
 import type { ScoreConfigRow } from "@/lib/score-config/rows";
 import { ScorePillarRow } from "../score-pillar-row";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "es", "fr", "it", "pl");
 
 function render(row: ScoreConfigRow, locale: Locale = "en"): string {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/sections.test.tsx b/src/components/settings/__tests__/sections.test.tsx
index 84ea150f2..ac9db4cbe 100644
--- a/src/components/settings/__tests__/sections.test.tsx
+++ b/src/components/settings/__tests__/sections.test.tsx
@@ -127,6 +127,9 @@ import { NotificationsSection } from "../notifications-section";
 // `thresholds-section.tsx` so the component name + filename match the
 // slug like every other settings section.
 import { ThresholdsSection } from "../thresholds-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const CALLBACK_URLS = {
   withings: "https://app.example/api/withings/callback",
diff --git a/src/components/settings/__tests__/settings-shell.test.tsx b/src/components/settings/__tests__/settings-shell.test.tsx
index 82a9db23a..3d858b2b8 100644
--- a/src/components/settings/__tests__/settings-shell.test.tsx
+++ b/src/components/settings/__tests__/settings-shell.test.tsx
@@ -59,6 +59,9 @@ import {
   SettingsShell,
   isSettingsSectionSlug,
 } from "../settings-shell";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function renderShell(props: {
   active?: (typeof SETTINGS_SECTION_SLUGS)[number];
diff --git a/src/components/settings/__tests__/sharing-section.test.tsx b/src/components/settings/__tests__/sharing-section.test.tsx
index 7cadc1354..b7ec19038 100644
--- a/src/components/settings/__tests__/sharing-section.test.tsx
+++ b/src/components/settings/__tests__/sharing-section.test.tsx
@@ -64,6 +64,9 @@ vi.mock("@tanstack/react-query", () => ({
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { SharingSection } from "../sharing-section";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(locale: "en" | "de" = "en") {
   return renderToStaticMarkup(
diff --git a/src/components/settings/__tests__/timezone-picker.test.tsx b/src/components/settings/__tests__/timezone-picker.test.tsx
index 5a52ca40f..05e4642d5 100644
--- a/src/components/settings/__tests__/timezone-picker.test.tsx
+++ b/src/components/settings/__tests__/timezone-picker.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { TimezonePicker } from "../timezone-picker";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.37 — the "Browser-Zeitzone übernehmen" / "Use browser timezone"
diff --git a/src/components/settings/integrations/__tests__/integration-card.test.tsx b/src/components/settings/integrations/__tests__/integration-card.test.tsx
index 9a1a09fdb..a630eaed4 100644
--- a/src/components/settings/integrations/__tests__/integration-card.test.tsx
+++ b/src/components/settings/integrations/__tests__/integration-card.test.tsx
@@ -39,6 +39,9 @@ import {
 } from "../oauth-integration-card";
 import type { IntegrationStatusViewModel } from "../shared";
 import { healthFixture } from "./health-fixture";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 // "Last data: today" only holds when the fixture's hours-ago stays on the same
 // local day, so the clock is pinned to midday rather than the wall clock.
diff --git a/src/components/targets/__tests__/consistency-strip.test.tsx b/src/components/targets/__tests__/consistency-strip.test.tsx
index 18639cc3e..b37778ded 100644
--- a/src/components/targets/__tests__/consistency-strip.test.tsx
+++ b/src/components/targets/__tests__/consistency-strip.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { ConsistencyStrip } from "../consistency-strip";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.4.25 W3e — `<ConsistencyStrip>` replaces the v1.4.22 per-card
diff --git a/src/components/timeline/__tests__/no-raw-code-guard.test.tsx b/src/components/timeline/__tests__/no-raw-code-guard.test.tsx
index 2c5e7c4f3..0859365b1 100644
--- a/src/components/timeline/__tests__/no-raw-code-guard.test.tsx
+++ b/src/components/timeline/__tests__/no-raw-code-guard.test.tsx
@@ -44,6 +44,9 @@ import { TimelineChronicle } from "../timeline-chronicle";
 import { layoutTimeline } from "../timeline-geometry";
 import { useSeriesValueFormat } from "../use-series-value-format";
 import { TODAY, item, wordsIn } from "./timeline-fixture";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 type Locale = "de" | "en";
 
diff --git a/src/components/timeline/__tests__/range-fields.test.tsx b/src/components/timeline/__tests__/range-fields.test.tsx
index 7c12cdbd7..82b4b6197 100644
--- a/src/components/timeline/__tests__/range-fields.test.tsx
+++ b/src/components/timeline/__tests__/range-fields.test.tsx
@@ -8,6 +8,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import type { DateFieldProps } from "@/components/ui/date-field";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 const fields: DateFieldProps[] = [];
 vi.mock("@/components/ui/date-field", () => ({
diff --git a/src/components/timeline/__tests__/timeline-components.test.tsx b/src/components/timeline/__tests__/timeline-components.test.tsx
index e2542bc63..ab0196b6f 100644
--- a/src/components/timeline/__tests__/timeline-components.test.tsx
+++ b/src/components/timeline/__tests__/timeline-components.test.tsx
@@ -30,6 +30,9 @@ import { TimelineChronicle } from "../timeline-chronicle";
 import { layoutTimeline } from "../timeline-geometry";
 import { useSeriesValueFormat } from "../use-series-value-format";
 import { TODAY, fullTimeline, readiness, wordsIn } from "./timeline-fixture";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 function render(node: React.ReactElement, locale: "de" | "en" = "de") {
   // A fresh client with no account answer: the unit preference resolves to
diff --git a/src/components/ui/__tests__/filter-bar.test.tsx b/src/components/ui/__tests__/filter-bar.test.tsx
index bde2d54db..8ab5fd593 100644
--- a/src/components/ui/__tests__/filter-bar.test.tsx
+++ b/src/components/ui/__tests__/filter-bar.test.tsx
@@ -5,6 +5,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider } from "@/lib/i18n/context";
 import { FilterBar, FilterBarDateRange, FilterBarSelect } from "../filter-bar";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de");
 
 /**
  * v1.16.1 — unified filter rail. SSR-markup guards for the shared
diff --git a/src/lib/i18n/__tests__/t-count.test.tsx b/src/lib/i18n/__tests__/t-count.test.tsx
index cf8f5ca10..186a44e05 100644
--- a/src/lib/i18n/__tests__/t-count.test.tsx
+++ b/src/lib/i18n/__tests__/t-count.test.tsx
@@ -3,6 +3,9 @@ import { renderToStaticMarkup } from "react-dom/server";
 
 import { I18nProvider, useTranslations } from "@/lib/i18n/context";
 import type { Locale } from "@/lib/i18n/config";
+import { primeLocales } from "@/__tests__/helpers/prime-locales";
+
+primeLocales("de", "pl");
 
 /**
  * `tCount` is the plural-aware `t` the components call.
diff --git a/vitest.setup.ts b/vitest.setup.ts
index ee1bfca15..2b48ae93d 100644
--- a/vitest.setup.ts
+++ b/vitest.setup.ts
@@ -1,35 +1,29 @@
 /**
  * Unit-test setup.
  *
- * Seed the client-side locale cache with every message bundle. In
- * production only EN ships statically; the active locale arrives as an
- * RSC prop from the root layout and other locales load via dynamic
- * import on switch (see `src/lib/i18n/load-locale.ts`). Tests mount
+ * Seed the client-side locale cache with the EN bundle. In production
+ * only the active locale reaches the client (boot script, then dynamic
+ * import on switch — see `src/lib/i18n/load-locale.ts`). Tests mount
  * `I18nProvider` standalone — often with `renderToStaticMarkup`, which
- * is synchronous and cannot await a dynamic import — so the cache is
- * primed up front and `t()` resolves every locale on the first render,
- * exactly like the server-handoff path does in the app.
+ * is synchronous and cannot await a dynamic import — so EN, the fallback
+ * floor of the t() chain, is primed up front.
+ *
+ * Only EN. Every catalog is several hundred kilobytes and this file runs
+ * once per test file, so priming all of them made setup the largest share
+ * of a unit run. A test that renders another locale primes it itself:
+ *
+ *   import deMessages from "../../../messages/de.json";
+ *   primeMessages("de", deMessages);
+ *
+ * Server-side translation (`getServerTranslator`, `shared-resolve`) holds
+ * every catalog on its own and needs no priming.
  */
 import { afterEach } from "vitest";
 import { settleBackgroundTasks } from "@/lib/logging/background-tasks";
 import { primeMessages } from "@/lib/i18n/load-locale";
-import deMessages from "./messages/de.json";
 import enMessages from "./messages/en.json";
-import esMessages from "./messages/es.json";
-import frMessages from "./messages/fr.json";
-import itMessages from "./messages/it.json";
-import plMessages from "./messages/pl.json";
-import koMessages from "./messages/ko.json";
-import nlMessages from "./messages/nl.json";
 
-primeMessages("de", deMessages);
 primeMessages("en", enMessages);
-primeMessages("es", esMessages);
-primeMessages("fr", frMessages);
-primeMessages("it", itMessages);
-primeMessages("pl", plMessages);
-primeMessages("ko", koMessages);
-primeMessages("nl", nlMessages);
 
 /**
  * Leave no background work in flight when a test ends.