metrics: stand up the weekly funnel job (FRE-202)

`marketing/metrics/weekly.md` has been a placeholder since the marketing tree
landed — it promised a funnel and the one thing that moved, and nothing
produced it. This adds the producer: one command reads the live databases and
rewrites the file.

`scripts/weekly-metrics.ts` writes `marketing/metrics/weekly.md` from
`VisitorAnalytics` (visits, downloads, campaigns) and the-nook's `trials`,
`licenses`, `activations` (the paid funnel). It needs four env vars —
TURSO_DB_URL/TOKEN and NOOK_DB_URL/TOKEN — and imports no server env, so the
job runs from a checkout that has no Stripe or Apple secrets.
`src/server/weekly-metrics.ts` holds the queries and the renderer, taking both
connections as arguments; the tests run them against an in-memory SQLite shaped
like production, the same way the backfill suite does.

The campaign breakdown groups exactly as `getAnalyticsSummary.topCampaigns`
does (top 10, untagged excluded), so the weekly read and /analytics cannot
drift into different label sets.

The first real report says more about the instrumentation than about demand,
and the renderer computes that rather than asserting it:

- every addressed row the table has ever held (12,035 of 12,048) is loopback,
  so "unique visitors" is one host and per-channel reach cannot be read;
- the landing door and the file route both write `/api/downloads/thenook`, so
  "download click" and "DMG served" are one label — one served click writes two
  rows, a failed click one, a Sparkle update one;
- `POST /api/the-nook/checkout` records nothing, so checkout start is only a
  page-view proxy;
- `VisitorAnalytics` has no host dimension, so the Nook's `/` is freno.me's `/`.

Those three gaps are reported beside the numbers, not papered over. Week 0
(2026-10-22 → 2026-10-29): visit 61, download 156, trial 2, checkout 0,
purchase 0, activation 0 — and the one thing that moved is the download stage,
0 → 156, because the label was introduced that week.

Tests: `bun test src/server/weekly-metrics.test.ts` — 12 pass, 0 fail. The full
suite's 15 failures are pre-existing: this checkout's .env lacks
NOOK_LICENSE_PRIVATE_KEY, NOOK_STRIPE_SK/WEBHOOK/PRICE and LINEAGE_JWT_SECRET,
and every failure is that env validation.

Scripts/ is gitignored, so `scripts/weekly-metrics.ts` was added with `-f`, the
way the existing tracked scripts are.

FRE-202

marketing/README.md

@@ -22,3 +22,12 @@ a human reviews and moves it to `approved/` → the human publishes from `approv
 under their own account → the artifact (or a pointer) lands in `posted/`.
 
 Nothing in `drafts/` or `pending/` is ever publishable, by anyone, by any means.
+
+## The weekly read
+
+`bun --env-file=.env scripts/weekly-metrics.ts` (or `bun run metrics:weekly`)
+rewrites `metrics/weekly.md` from the live databases: the staged funnel, the
+campaign breakdown (`getAnalyticsSummary.topCampaigns`' grouping), and the one
+stage that moved. It needs `TURSO_DB_URL`, `TURSO_DB_TOKEN`, `NOOK_DB_URL` and
+`NOOK_DB_TOKEN` — no other production secret. The file is generated; never
+hand-edit it. The numbers are engineering's; the interpretation is the CMO's.