perf(bench): add a large-account seed and a request benchmark

scripts/bench/seed-large-account.ts (moved from scripts/, extended) writes
one synthetic account of ten years: 1,265,561 measurement rows across the
main types and five sources (Apple Health dense spot rows, Withings blood
pressure and scale, a weekly manual weight, three years of Oura nightly
values, 90 days of Nightscout CGM), `stats:` and per-sample cumulative rows,
nightly sleep stages, 3,020 workouts, 1,095 mood entries and three
medications with 3,285 intake events. Everything goes in through set-based
INSERT … SELECT generate_series; values and timestamps are functions of the
row index and `--anchor`, so a run is reproducible. The rollup tier is
folded with recomputeUserRollups, as the boot backfill does, and the tables
are analysed. About 80 s on the Mac mini.

scripts/bench/run.ts boots the production build once with every role (so
the queues exist), then measures against a web-only process under the
production heap ceiling: p50, p95 and max latency and SQL statements per
request (pg_stat_statements, read once nothing is in flight and the count
holds still) for /api/auth/me, the dashboard summary and snapshot, the pulse
series over 30, 365 and 3650 days, the day view, insights health status and
correlations, each cold (caches evicted by a one-row manual-sync ingest
before every request) and warm, plus a 5,000-row batch ingest as ten
requests of 500. It writes JSON and a markdown table.

docs/contributing/benchmarks.md describes the setup against a throwaway
Postgres in Docker with the production pg_stat_statements settings.

scripts/README.md

@@ -28,6 +28,7 @@ typecheck.
 - **`repair-intake-anomalies.ts`** — repair historic medication-ledger defects (duplicate dose-slot rows, implausible `taken_at`); dry-run by default, see `docs/ops/intake-repair.md`.
 - **`backfill-rollups.ts`**, **`drain-per-sample-cumulative.ts`**, **`backfill-mood-note-column.ts`** — historical data backfills (note: the boot-time `rollup-full-backfill` queue handles new accounts automatically; the CLI is the manual fallback).
 - **`seed-demo.ts`** + **`seed-demo-v15.sql`** — populate a demo tenant.
+- **`bench/`** — `seed-large-account.ts` (a synthetic ten-year account of about 1.26 million measurement rows) and `run.ts` (latency and SQL statements per request against it); see `docs/contributing/benchmarks.md`. Results land in `bench/results/`.
 - **`test-notifications.ts`** — exercise the notification dispatcher + reminder check.
 - **`fetch-geolite2.sh`** — download the MaxMind GeoLite2 MMDBs (needs a licence key) before `docker build`.
 - **`install-hooks.sh`** — install the local git hooks.