chore(release): v1.4.39.3 — dashboard slim/thick merge robustness and list-page precision

The post-deploy CI for v1.4.39.2 surfaced eight e2e failures across
chromium-desktop and chromium-mobile (chart-overlay-controls,
dashboard, charts-mobile, measurement-flow) that all routed through
two narrow regressions and one durable test-fixture gap.

### Fixed

- Dashboard slim/thick merge no longer blanks the tile strip when the
  slim slice resolves with an empty summaries record. The v1.4.39.2
  inline `slim?.summaries ?? thick?.summaries` short-circuited on
  JavaScript's truthy-empty-object even when thick carried the full
  payload. The merge moved to a pure `mergeSlimAndThickAnalytics`
  helper that uses object emptiness as the discriminator: populated
  slim still wins on overlapping fields (progressive-paint contract
  preserved), empty slim falls through to thick, both empty leaves
  the dashboard's data-floor gates to render the appropriate empty
  state. Eight new behaviour-level unit tests cover the edge cases.
- `MeasurementList` non-grouped rows now preserve decimal precision
  on both the desktop table and the mobile card grid. The v1.4.37 W7c
  collapsed-list view passed every value through `fmt.integer`, which
  kept the per-day step / activity aggregates correct but silently
  truncated single weight / body-fat / temperature readings — 78.4 kg
  rendered as "78 kg". Grouped rows (cumulative HK type day
  aggregates) stay on `fmt.integer` because their readings are
  integer-only; non-grouped rows now use `fmt.number` which honours
  up to three fraction digits without forcing a minimum.

### Changed

- Playwright route mocks for `/api/analytics` migrate from the
  literal `**/api/analytics` string glob to the regex form
  `/\/api\/analytics(\?|$)/` across every authenticated spec. The
  string glob does not match the sliced URL form
  `/api/analytics?slice=summaries` the v1.4.39.2 dashboard split
  fires alongside the thick request, so the slim request fell
  through to the real route on the seeded test user that returns
  empty summaries. Ten specs migrate: dashboard,
  chart-overlay-controls, measurement-flow, charts-mobile, a11y,
  v1427-responsive-sheet, v1427-coach-launch,
  v1427-measurements-add-param, v1427-insights-empty-state,
  onboarding-tour-passthrough. The regex form is the durable
  alignment with the v1.4.37 W-CI lesson that already swept
  `onboarding-flicker.spec.ts` and `mobile-viewport.spec.ts`.

### Notes

- No schema migration. Runtime + test-fixture-only changes.
- `pnpm test --run` green at 4662 / 4663 (1 long-standing skip).
- Full Playwright suite green at 116 passing / 36 skipped / 152 total
  on both `chromium-desktop` and `chromium-mobile` profiles, against
  the production Next.js build. Closes every failure from CI run
  26213226723.

src/app/page.tsx

@@ -66,6 +66,7 @@ import { useTranslations, useFormatters } from "@/lib/i18n/context";
 import { queryKeys } from "@/lib/query-keys";
 import { useAnalyticsQuery } from "@/lib/queries/use-analytics-query";
 import type { DataSummary } from "@/lib/analytics/trends";
+import { mergeSlimAndThickAnalytics } from "@/lib/analytics/merge-slim-thick";
 import { getBpTargets } from "@/lib/analytics/bp-targets";
 import {
   buildTrafficLightBands,
@@ -245,28 +246,30 @@ export default function DashboardPage() {
   const analyticsSlimQuery = useAnalyticsQuery({ slice: "summaries" });
   const analyticsThickQuery = useAnalyticsQuery();
   const data = useMemo<AnalyticsData | undefined>(() => {
-    const slim = analyticsSlimQuery.data;
-    const thick = analyticsThickQuery.data;
-    if (!slim && !thick) return undefined;
-    // Slim wins on overlapping fields when both have resolved — slim
-    // and thick compute `summaries` / `lastSeenByType` from the same
-    // SQL helpers so the values agree, and reading from whichever
-    // resolves first keeps the tile strip painting as soon as either
-    // query lands.
-    const summaries =
-      slim?.summaries ?? thick?.summaries ?? ({} as Record<string, DataSummary>);
-    const lastSeenByType =
-      slim?.lastSeenByType ?? thick?.lastSeenByType;
+    // v1.4.39.3 — the merge moved to `mergeSlimAndThickAnalytics` so
+    // the empty-slim-vs-populated-thick edge has direct unit
+    // coverage. Pre-fix the inline `slim?.summaries ?? thick?.summaries`
+    // short-circuited on a truthy-but-empty `{}` from the slim slice
+    // and blanked the tile strip even when thick carried the full
+    // payload — the regression Marc's v1.4.39.3 e2e CI flagged across
+    // eight dashboard / chart specs. The helper falls back to thick
+    // when slim resolves with no content and otherwise keeps the
+    // v1.4.39.2 slim-wins-first progressive-paint contract.
+    const merged = mergeSlimAndThickAnalytics(
+      analyticsSlimQuery.data,
+      analyticsThickQuery.data,
+    );
+    if (!merged) return undefined;
     return {
-      summaries,
-      lastSeenByType,
-      bpInTargetPct: (thick?.bpInTargetPct ?? null) as number | null,
-      bpInTargetPct7d: thick?.bpInTargetPct7d ?? null,
-      bpInTargetPct30d: thick?.bpInTargetPct30d ?? null,
-      bpInTargetPctAllTime: thick?.bpInTargetPctAllTime ?? null,
-      bpInTargetPctPriorMonth: thick?.bpInTargetPctPriorMonth ?? null,
-      bpInTargetPctPriorYear: thick?.bpInTargetPctPriorYear ?? null,
-      glucoseByContext: thick?.glucoseByContext as
+      summaries: merged.summaries,
+      lastSeenByType: merged.lastSeenByType,
+      bpInTargetPct: merged.bpInTargetPct,
+      bpInTargetPct7d: merged.bpInTargetPct7d,
+      bpInTargetPct30d: merged.bpInTargetPct30d,
+      bpInTargetPctAllTime: merged.bpInTargetPctAllTime,
+      bpInTargetPctPriorMonth: merged.bpInTargetPctPriorMonth,
+      bpInTargetPctPriorYear: merged.bpInTargetPctPriorYear,
+      glucoseByContext: merged.glucoseByContext as
         | Record<string, DataSummaryType>
         | undefined,
     };