fix(i18n): carry the count in One strings where one is more than 1

The plural tier comes from CLDR, and in Russian the one category also
holds 21, 31, 101, while French and Brazilian Portuguese file 0 there.
Thirty One strings in those bundles spelled out the 1, so 21 days read
as one day. They now take {count}, as do two Russian One strings that
spelled the number as a word, and every direct call of such a key passes
the count. A guard finds the locales whose one is wider than 1 from
Intl.PluralRules and holds both ends.

src/components/admin/invite-tokens-section.tsx

@@ -290,7 +290,7 @@ export function InviteTokensSection() {
     const days = daysUntil(invite.expiresAt, now);
     if (days <= 0) return "—";
     return days === 1
-      ? t("admin.invites.expiresInDaysOne")
+      ? t("admin.invites.expiresInDaysOne", { count: days })
       : t("admin.invites.expiresInDaysOther", { count: days });
   }
 

src/components/charts/trend-hint.tsx

@@ -26,7 +26,7 @@ export function TrendHint({ count }: TrendHintProps) {
 
   const description =
     result.remaining === 1
-      ? t("trendHints.remainingOne")
+      ? t("trendHints.remainingOne", { count: result.remaining })
       : t("trendHints.remainingMany", { count: result.remaining });
 
   return (

src/components/illness/illness-insights-card.tsx

@@ -74,7 +74,9 @@ export function IllnessInsightsCard({
           <div className="space-y-4 text-sm">
             <p className="text-foreground">
               {data!.episodeCount === 1
-                ? t("illness.insights.countOne")
+                ? t("illness.insights.countOne", {
+                    count: data!.episodeCount,
+                  })
                 : t("illness.insights.countOther", {
                     count: data!.episodeCount,
                   })}

src/components/illness/illness-view.tsx

@@ -77,7 +77,7 @@ function NestedEpisodes({ episodes }: { episodes?: IllnessEpisodeDTO[] }) {
       {allFlares ? (
         <p className="text-muted-foreground text-xs font-medium">
           {count === 1
-            ? t("illness.flares.countOne")
+            ? t("illness.flares.countOne", { count })
             : t("illness.flares.countOther", { count })}
         </p>
       ) : null}

src/components/insights/ecg-cross-link.tsx

@@ -52,7 +52,7 @@ export function EcgCrossLink({ enabled = true, className }: EcgCrossLinkProps) {
 
   const countText =
     count === 1
-      ? t("insights.ecg.crossLink.recordingsOne")
+      ? t("insights.ecg.crossLink.recordingsOne", { count })
       : t("insights.ecg.crossLink.recordingsMany", { count });
   const resultText = resultKey
     ? t("insights.ecg.crossLink.latestResult", { result: t(resultKey) })

src/components/insights/glucose/glucose-advanced-disclosure.tsx

@@ -123,6 +123,7 @@ export function GlucoseAdvancedDisclosure({
                     {summary.count === 1
                       ? t(
                           "insights.bloodGlucose.clinical.advanced.byContext.readingsShortOne",
+                          { count: summary.count },
                         )
                       : t(
                           "insights.bloodGlucose.clinical.advanced.byContext.readingsShort",

src/components/insights/glucose/glucose-clinical-panel.tsx

@@ -90,14 +90,14 @@ export function GlucoseClinicalPanel() {
     const hasAny = clinical.readingCount > 0;
     const readingsLabel =
       clinical.readingCount === 1
-        ? t("insights.bloodGlucose.clinical.readingsCountOne")
+        ? t("insights.bloodGlucose.clinical.readingsCountOne", { count: 1 })
         : t("insights.bloodGlucose.clinical.readingsCount", {
             count: clinical.readingCount,
           });
     const spanDays = Math.max(1, Math.round(clinical.actualSpanDays));
     const daysLabel =
       spanDays === 1
-        ? t("insights.bloodGlucose.clinical.daysCountOne")
+        ? t("insights.bloodGlucose.clinical.daysCountOne", { count: spanDays })
         : t("insights.bloodGlucose.clinical.daysCount", { days: spanDays });
 
     return (

src/components/insights/intraday-pulse-chart.tsx

@@ -183,12 +183,12 @@ export function IntradayPulseChart({
       : t("insights.intradayPulse.caption");
 
   const coverageNote = coverage
-    ? coverage.readingCount === 1
-      ? t("insights.intradayPulse.coverageOne", { hours: coverage.hours })
-      : t("insights.intradayPulse.coverageMany", {
-          count: coverage.readingCount,
-          hours: coverage.hours,
-        })
+    ? t(
+        coverage.readingCount === 1
+          ? "insights.intradayPulse.coverageOne"
+          : "insights.intradayPulse.coverageMany",
+        { count: coverage.readingCount, hours: coverage.hours },
+      )
     : null;
 
   const dayLabel = isToday

src/components/medications/medication-table.tsx

@@ -698,7 +698,7 @@ function MedicationTableRowItem({
           )}
         >
           {stock === 1
-            ? t("medications.tableStockDoseOne")
+            ? t("medications.tableStockDoseOne", { count: stock })
             : t("medications.tableStockDoses", { count: stock })}
         </span>
         {runwayDays !== null && (

src/components/medications/scheduling/schedule-history-timeline.tsx

@@ -82,6 +82,12 @@ interface ScheduleRevisionsResponse {
   revisions: ScheduleRevisionRow[];
 }
 
+/** The "show earlier eras" toggle, by how many there are. */
+const SHOW_ERAS_KEY = {
+  one: "medications.detail.zeitplan.history.showErasOne",
+  other: "medications.detail.zeitplan.history.showErasOther",
+} as const;
+
 /**
  * Dose-time readout of one era: the union of its entries' times,
  * deduped + sorted ("07:00 / 19:00"). PRN-only eras have no times —
@@ -284,11 +290,9 @@ export function ScheduleHistoryTimeline({
             />
             {expanded
               ? t("medications.detail.zeitplan.history.hideEras")
-              : revisions.length === 1
-                ? t("medications.detail.zeitplan.history.showErasOne")
-                : t("medications.detail.zeitplan.history.showErasOther", {
-                    count: revisions.length,
-                  })}
+              : t(SHOW_ERAS_KEY[revisions.length === 1 ? "one" : "other"], {
+                  count: revisions.length,
+                })}
           </Button>
         )}
         <Button

src/lib/i18n/__tests__/plural-one-carries-count.test.ts

@@ -0,0 +1,152 @@
+/**
+ * A `*One` string carries the count wherever "one" is more than 1.
+ *
+ * `pluralTier` takes the tier from CLDR, and in several shipped languages the
+ * "one" category is not the number 1 alone: Russian files 21, 31, 101 under
+ * it, French and Brazilian Portuguese file 0 there. A `*One` value that
+ * spells the number out ("за 1 день") then reads "1" for 21 days. In those
+ * locales the value takes the `{count}` that `tCount` passes, and a call that
+ * reaches such a key directly passes the count too.
+ *
+ * Both checks are functions of their input, and each is shown failing once on
+ * an input built to break it.
+ */
+import { describe, expect, it } from "vitest";
+
+import { readSourceFolder } from "@/__tests__/helpers/source-files";
+import { resolveIntlLocale } from "@/lib/format-locale";
+
+import { locales, type Locale } from "../config";
+import { pluralKey } from "../plural";
+import { getServerTranslator } from "../server-translator";
+import { allMessages } from "../shared-resolve";
+
+/** Locales whose CLDR "one" category holds an integer other than 1. */
+function localesWithWideOne(): Locale[] {
+  return locales.filter((locale) => {
+    const rules = new Intl.PluralRules(resolveIntlLocale(locale));
+    for (let n = 0; n <= 1000; n++) {
+      if (n !== 1 && rules.select(n) === "one") return true;
+    }
+    return false;
+  });
+}
+
+function flatten(
+  node: unknown,
+  prefix = "",
+  out = new Map<string, string>(),
+): Map<string, string> {
+  if (typeof node === "string") {
+    out.set(prefix, node);
+  } else if (node && typeof node === "object") {
+    for (const [key, value] of Object.entries(node)) {
+      flatten(value, prefix ? `${prefix}.${key}` : key, out);
+    }
+  }
+  return out;
+}
+
+function bundle(locale: Locale): Map<string, string> {
+  return flatten(allMessages[locale]);
+}
+
+/** A digit 1 standing on its own, not part of a larger number. */
+const BARE_ONE = /(?<!\d)1(?!\d)/;
+
+/** `*One` values that spell out the 1 instead of carrying `{count}`. */
+function spelledOutOnes(messages: Map<string, string>): string[] {
+  const offenders: string[] = [];
+  for (const [key, value] of messages) {
+    if (!key.endsWith("One")) continue;
+    if (BARE_ONE.test(value) && !value.includes("{count}")) {
+      offenders.push(key);
+    }
+  }
+  return offenders.sort();
+}
+
+/**
+ * `t("<key>One")` without a `count` param, for a key whose value needs
+ * `{count}`: no params at all, or an inline params object that lacks it.
+ */
+function directCallsWithoutCount(
+  sources: ReadonlyArray<{ file: string; text: string }>,
+  needsCount: ReadonlySet<string>,
+): string[] {
+  const call = /\bt\(\s*"([\w.]+One)"\s*(?:,\s*\{([^}]*)\})?\s*,?\s*\)/g;
+  const offenders: string[] = [];
+  for (const { file, text } of sources) {
+    for (const match of text.matchAll(call)) {
+      const params = match[2];
+      if (params !== undefined && /\bcount\b/.test(params)) continue;
+      if (needsCount.has(match[1]!)) offenders.push(`${file}: ${match[1]}`);
+    }
+  }
+  return offenders.sort();
+}
+
+describe("plural One strings", () => {
+  const wide = localesWithWideOne();
+
+  it("finds the locales whose one is not just 1", () => {
+    expect(wide).toEqual(expect.arrayContaining(["ru", "fr", "pt-BR"]));
+    expect(wide).not.toContain("en");
+    expect(wide).not.toContain("pl");
+  });
+
+  it("says 21 days in Russian, not 1", () => {
+    const { t } = getServerTranslator("ru");
+    expect(
+      t(pluralKey("timeline.symptoms.days", 21, "ru"), { count: 21 }),
+    ).toBe("за 21 день");
+  });
+
+  it("gives every One string in those locales the count", () => {
+    const offenders = wide.flatMap((locale) =>
+      spelledOutOnes(bundle(locale)).map((key) => `${locale}: ${key}`),
+    );
+    expect(offenders).toEqual([]);
+  });
+
+  it("passes the count wherever such a key is called directly", () => {
+    const needsCount = new Set<string>();
+    for (const locale of wide) {
+      for (const [key, value] of bundle(locale)) {
+        if (key.endsWith("One") && value.includes("{count}")) {
+          needsCount.add(key);
+        }
+      }
+    }
+    expect(needsCount.size).toBeGreaterThan(0);
+    const sources = readSourceFolder("src", {
+      floor: 1000,
+      include: (rel) =>
+        !rel.includes("__tests__") && !rel.includes("generated/"),
+    }).map(([file, text]) => ({ file, text }));
+    expect(directCallsWithoutCount(sources, needsCount)).toEqual([]);
+  });
+
+  it("would catch a spelled-out one and a call without the count", () => {
+    expect(
+      spelledOutOnes(
+        new Map([
+          ["timeline.symptoms.daysOne", "за 1 день"],
+          ["timeline.symptoms.daysOther", "за {count} дней"],
+          ["a.bOne", "за {count} день"],
+          ["a.cOne", "Скрыто (11)"],
+        ]),
+      ),
+    ).toEqual(["timeline.symptoms.daysOne"]);
+    expect(
+      directCallsWithoutCount(
+        [
+          { file: "x.tsx", text: 'n === 1 ? t("a.bOne") : t("a.bOther")' },
+          { file: "y.tsx", text: 't("a.bOne", { hours: h })' },
+          { file: "z.tsx", text: 't("a.bOne", { count: n, hours: h })' },
+        ],
+        new Set(["a.bOne"]),
+      ),
+    ).toEqual(["x.tsx: a.bOne", "y.tsx: a.bOne"]);
+  });
+});