feat(api,web): real-time newsletter progress via Durable Objects

[Irere123]

Summary

Adds a real-time layer for newsletter sends and subscriber stats, built on two SQLite-backed Cloudflare Durable Objects surfaced over WebSockets.

• CampaignProgress (per campaign): coordination point for a send. The email worker seeds totals via start(), each batch reports completion (idempotent by batchIndex), and analytics/unsubscribe feed engagement. When the final batch lands it marks the campaign SENT and records totalSent in D1 — the queue fan-out previously had no "all batches done" signal, so campaigns were stuck on SENDING and totalSent was always 0 (click rate always 0%).
• WriterStats (per writer): subscriber lifecycle mutations re-read authoritative counts from D1 and broadcast them.

Cookie-authenticated WS routes (/realtime/campaigns/:id, /realtime/subscribers) forward to the DOs using the hibernation API. All notifiers are best-effort, so realtime can never break a send or mutation.

Frontend adds a reconnecting WS channel hook plus useCampaignRealtime / useSubscriberStatsRealtime: a live send progress bar + engagement on the campaign detail page, and live subscriber stat cards that refresh the list as people subscribe, confirm, and unsubscribe.

Validation

• API tsc --noEmit: clean.
• wrangler --dry-run bundles the worker with both DOs registered; wrangler types accepted the bindings + v1 migration.
• Web typecheck shows only pre-existing cross-project warnings (verified against a stashed baseline); no new real errors.

Notes

• On wrangler deploy --env staging, the v1 DO migration applies on first deploy.
• Open-tracking remains a placeholder (no open_events table), so the live Opens counter reflects pixel hits for the current send session only.

🤖 Generated with Claude Code