fix(rollups): trail the rollup window from the caller's moment

readBestGranularityRollups opened its window at the wall clock, while the
live fallback beside it used the caller's now. A read anchored on another
moment saw different days depending on whether the account already had
DAY buckets; the Today overview's integration test turned red once its
fixed morning fell out of the wall-clock window. Every caller that holds a
now passes it through.

src/lib/analytics/range-delta.ts

@@ -316,6 +316,8 @@ export async function computeRangeDelta(
     userId,
     type,
     windowDays * 2,
+    undefined,
+    new Date(now),
   );
   if (!resolved) {
     const empty: WindowAggregate = {

src/lib/illness/correlation-read.ts

@@ -217,7 +217,13 @@ async function readWindowMeans(
       1,
       Math.ceil((to.getTime() - from.getTime()) / MS_PER_DAY),
     );
-    const resolved = await readBestGranularityRollups(userId, type, windowDays);
+    const resolved = await readBestGranularityRollups(
+      userId,
+      type,
+      windowDays,
+      undefined,
+      now,
+    );
     if (
       resolved &&
       resolved.granularity === "DAY" &&

src/lib/insights/derived/baseline.ts

@@ -274,7 +274,13 @@ export async function readDayMeanSeries(
     // band from WEEK/MONTH `sd`, and the center reads the DAY `mean`
     // which composes exactly. `readBestGranularityRollups` with a
     // window < 91 days resolves to DAY by construction.
-    const resolved = await readBestGranularityRollups(userId, type, windowDays);
+    const resolved = await readBestGranularityRollups(
+      userId,
+      type,
+      windowDays,
+      undefined,
+      now,
+    );
     if (
       resolved &&
       resolved.granularity === "DAY" &&

src/lib/insights/graded-series.ts

@@ -537,6 +537,7 @@ export async function buildGradedSeriesWithRollups(
     type,
     365,
     priority,
+    now,
   );
   // Yearly slice: route a multi-year window through the tier.
   const yearlyRouted = await readBestGranularityRollups(
@@ -544,6 +545,7 @@ export async function buildGradedSeriesWithRollups(
     type,
     1095,
     priority,
+    now,
   );
 
   const monthlyCovered =

src/lib/rollups/measurement-read-wmy.ts

@@ -116,12 +116,16 @@ export async function readBestGranularityRollups(
   type: MeasurementType,
   windowDays: number,
   userPriorityJson?: unknown,
+  now: Date = new Date(),
 ): Promise<{
   granularity: RollupGranularity;
   rows: RollupBucketRow[];
 } | null> {
   if (!Number.isFinite(windowDays) || windowDays <= 0) return null;
-  const since = new Date(Date.now() - windowDays * 24 * 60 * 60 * 1000);
+  // The window trails the caller's `now`, so a read anchored on another
+  // moment than the wall clock sees the same days through the rollups as
+  // through the live fallback.
+  const since = new Date(now.getTime() - windowDays * 24 * 60 * 60 * 1000);
   // v1.11.1 — load the source-priority blob once and thread it into every
   // granularity probe so the collapse never re-queries the user per floor.
   const priority =