fix(measurements): page day sums and sleep nights in SQL

The day-grouped list read the newest `limit` raw rows (the web asked
for 5000), folded them into days and returned every day at once: one
page of thousands of rows, and every day older than the 5000th raw row
missing without a word. The sleep list did the same at a year.

Both now pick the page in Postgres. The day mode selects the page's
local days with the distinct-day total from `COUNT(*) OVER ()` in the
same query, then folds only those days into per-source groups in SQL
and lets the source ladder choose among the groups, so no raw row
reaches the process. The sleep mode cuts sessions with the same gap
rule as the reconstruction, pages wake days the same way and reads only
the page's stage rows; the 365-day cut and `meta.windowFrom` are gone.
A sleep page holds at most 1000 nights, echoed in `meta.limit`.

The web list pages both modes at 25 like the per-sample list. The
`partial` day marker is dropped from the contract; no day is cut any
more.

Refs #1245

src/components/measurements/measurement-list.tsx

@@ -581,7 +581,7 @@ export function MeasurementList({
   // v1.11.5 — SLEEP_DURATION is collapsed server-side to one row per
   // night (TIME ASLEEP), so the list paints per-night rows with a
   // chevron drilling into the night's stage segments. Like the
-  // cumulative branch it returns a single page of synthesised rows.
+  // cumulative branch it pages server-side over its synthesised rows.
   const isSleepFilter = typeFilter === "SLEEP_DURATION";
   const isDayGroupedFilter = isCumulativeFilter || isSleepFilter;
 
@@ -634,30 +634,11 @@ export function MeasurementList({
       params.set("offset", String((page - 1) * PAGE_SIZE));
       params.set("sortBy", sortBy);
       params.set("sortDir", sortDir);
-      if (isCumulativeFilter) {
-        params.set("groupBy", "day");
-        // The collapsed mode synthesises one row per day from the
-        // window of raw samples. Use the server-side ceiling (5000)
-        // so a chatty pre-drain Apple-Watch account (≈200 per-sample
-        // chunks/day on the busiest days) still fills several screens
-        // of daily rows before the nightly drain reduces each day to
-        // a single `stats:` row. Post-drain the scan is trivially
-        // short — every day reduces to 1 row.
-        params.set("limit", "5000");
-        // The synthesised rows live entirely in the collapse branch
-        // — pagination/offset don't apply on the server side. Reset
-        // the offset so a sort-direction flip doesn't paginate into
-        // an empty slice.
-        params.set("offset", "0");
-      } else if (isSleepFilter) {
-        // v1.11.5 — the route auto-collapses SLEEP_DURATION to one row
-        // per night (no `groupBy` param needed). Request a wide limit
-        // so the per-night list spans the trailing year the route
-        // bounds the read to; offset doesn't apply to the synthesised
-        // rows.
-        params.set("limit", "366");
-        params.set("offset", "0");
-      }
+      // The day-grouped modes page over days, the same 25 per page as
+      // the per-sample list: `groupBy=day` folds each cumulative day to
+      // its sum, and SLEEP_DURATION collapses to one row per night
+      // without a param.
+      if (isCumulativeFilter) params.set("groupBy", "day");
       return apiGet<{
         measurements: Measurement[];
         meta: { total: number };
@@ -839,14 +820,9 @@ export function MeasurementList({
     blocked: updateMutation.isPending || deleteMutation.isPending,
   });
 
-  // v1.4.37 W7c — the collapsed daily view paints up to 5000
-  // synthesised rows in one shot (one row per day for the
-  // configured window). Pagination would force a second server
-  // round-trip that re-fires the same scan, so the day-grouped
-  // path collapses to a single page. Per-sample lists continue to
-  // paginate at PAGE_SIZE = 25.
-  const totalPages =
-    data && !isDayGroupedFilter ? Math.ceil(data.meta.total / PAGE_SIZE) : 0;
+  // Every mode pages server-side at PAGE_SIZE: the per-sample list over
+  // rows, the day-grouped modes over days or nights (#1245).
+  const totalPages = data ? Math.ceil(data.meta.total / PAGE_SIZE) : 0;
 
   function startEdit(measurement: Measurement) {
     if (onEdit) {