Epic: Analytics — Fathom-tier (gaps & correctness)

Polish the privacy-first analytics: verify-install, ad-blocker resilience, CORS, accurate uniques, real digests.

Tracks (6):

• #84 — Install: "verify installation / send test event" in Settings
• #85 — Ingest: stealth/first-party proxy path for ad-blocker resilience (+ docs)
• #86 — Ingest: ensure CORS on /collect for cross-domain installs
• #87 — Data: accurate unique-visitor counting
• #88 — Privacy: replace predictable cookieless salt with a secret-seeded daily rotation
• #89 — Reports: scheduled email digests (weekly/monthly) actually send

Part of the Fathom + Sentry product backlog. See #44 for the original roadmap.

All six tracks shipped — closing the epic.

• #84 verify-installation button (synthetic event through real /collect + read-back pass/fail)
• #85 stealth ?stealth=true script variant + first-party proxy guide (nginx/CF Worker/Netlify)
• #86 CORS preflights on every collect endpoint (cross-domain installs work)
• #87 unique-visitor definition fixed + documented (daily-salted hash; exact within a day, summed daily uniques across days; SQS isUnique hardcode fixed)
• #88 secret-seeded daily salt (HMAC-SHA256, non-reproducible without the server secret)
• #89 scheduled email digests actually send (jobs runtime)