perf(insights): route daily chart fetches through rollup buckets

The Insights trends row fires three parallel
GET /api/measurements?type=…&aggregate=daily&limit=5000 requests on
mount (BP_SYS / BP_DIA / WEIGHT). The legacy date_trunc path scanned
the measurements table each time — ~3 s per call on Marc's account.

Add a `source=rollup` opt-in on the listMeasurements schema. When set
alongside `aggregate=daily` the route reads from measurement_rollups
DAY buckets instead, swapping a full-table scan for a small indexed
read against the ~5 k-row rollup table. Cumulative HK metrics get
mean * count to reconstruct the daily SUM the chart expects.

The chart-data client opts in for every windowDays > 7 fetch so the
trends row + every sub-page chart benefit. When the rollup returns
zero buckets for the requested window the route falls through to the
live aggregate so brand-new accounts still render their first chart
correctly.

src/components/charts/health-chart.tsx

@@ -585,8 +585,20 @@ export function HealthChart({
         // Recharts paint cost ~50× on continuous-monitoring accounts.
         // Short windows keep raw fetching so hour-by-hour detail
         // stays visible.
+        //
+        // v1.4.36 W1 — also route the daily aggregate through the
+        // persistent rollup buckets via `source=rollup`. The route
+        // reads from `measurement_rollups` instead of running a live
+        // `date_trunc` scan over the raw measurements table; the
+        // three parallel daily fetches on the Insights trends row
+        // (BP_SYS / BP_DIA / WEIGHT) drop from ~3 s each to a small
+        // indexed read against the ~5 k-row rollup table. The server
+        // falls back to live SQL when the rollup is empty for the
+        // requested window so brand-new accounts still see a chart
+        // on their first render.
         if (fetchWindow.windowDays > 7) {
           typeParams.set("aggregate", "daily");
+          typeParams.set("source", "rollup");
         }
 
         const res = await fetch(`/api/measurements?${typeParams}`);