fix(measurements): cut drain days in the zone the server publishes for the account

src/lib/measurements/__tests__/consolidation-scan-paged.test.ts

@@ -1,5 +1,10 @@
 import { describe, expect, it, vi } from "vitest";
 
+const appSettings = vi.hoisted(() => ({
+  findUnique: vi.fn(async () => ({ defaultUserTimezone: "America/New_York" })),
+}));
+vi.mock("@/lib/db", () => ({ prisma: { appSettings } }));
+
 import {
   bucketRowsByDay,
   iterateDayBuckets,
@@ -303,4 +308,29 @@ describe("runConsolidation — streamed walk", () => {
     expect(result.stoppedEarly).toBe(true);
     expect(findMany).toHaveBeenCalledTimes(1);
   });
+
+  it("cuts days in the zone the server publishes for the account", async () => {
+    // A stored zone the server sets aside reads as the instance default, as
+    // it does for `/api/auth/me` and the hour-bucket writer; never as the
+    // drain's own fallback.
+    const findMany = buildPagingFindMany(hourlyRows(1));
+    const base = params(findMany, async () => ({
+      kind: "written" as const,
+      sourceRowsRemoved: 0,
+    }));
+    const zones: string[] = [];
+    await runConsolidation({
+      ...base,
+      prismaClient: {
+        user: {
+          findMany: vi
+            .fn()
+            .mockResolvedValue([{ id: "user-2", timezone: null }]),
+        },
+        measurement: { findMany },
+      } as unknown as PrismaClient,
+      onUserStart: ({ tz }) => zones.push(tz),
+    });
+    expect(zones).toEqual(["America/New_York"]);
+  });
 });

src/lib/measurements/consolidation-base.ts

@@ -44,6 +44,7 @@ import {
   type PerSampleRow,
 } from "./consolidation-tz";
 import { DEFAULT_TIMEZONE } from "@/lib/tz/format";
+import { resolveStoredTimezone } from "@/lib/tz/resolver";
 
 // Re-export the shared grace constant so the established
 // `consolidation-base` import surface stays unchanged for callers.
@@ -454,7 +455,12 @@ export async function runConsolidation<TType extends MeasurementType>(
   const users = await loadConsolidationUsers(prismaClient, options.userId);
 
   walk: for (const user of users) {
-    const tz = resolveUserTimezone(user.timezone);
+    // The zone the server publishes for the account (`/api/auth/me`), which
+    // is the zone the phone cuts its `stats:` days and hour buckets in and
+    // the one the hour-bucket writer stores them under. A stored value the
+    // server sets aside falls back to the instance default here as it does
+    // there, never to a second fallback of the drain's own.
+    const tz = await resolveStoredTimezone(user.timezone);
     // Aligned to the account's local day: a day is folded whole or not at
     // all, never in two runs (see `foldBoundary`).
     const cutoffAt =