test: cover NATS bridge + Todoist scheduler; ADR-0010

- bus.test.ts: 4 cases for the new onPublish hook contract
- nats.test.ts: stream creation idempotency + JSON publish bridge
- scheduler.test.ts: startup delay, fan-out, per-user failure isolation
- ADR-0010 documents the bridge-don't-replace decision and the
  Todoist scheduler isolation, plus open follow-ups (#98 ml/serving
  consumer, #54 protobuf migration, graceful shutdown, metrics)
- README/overview/services README reflect the bridged event substrate
- CLAUDE.md gains a "don't nats.publish() directly" rule
- .env.example documents NATS_URL + TODOIST_SYNC_INTERVAL_MS

Verified in deployment 2026-04-18: api -> nats bridge connects on
boot, signals + feedback streams created, scheduler tick logs
"todoist sync: 1 ok, 0 failed (1 users)" within 10s. Closes #21, #22.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

README.md

@@ -143,7 +143,7 @@ Goal: tips are picked, not drawn from a hat — and they arrive at the right mom
 - [x] Shadow-policy registry: run N shadow policies per request, log picks without serving them (#56)
 - [ ] Quiet-hours + dedupe for push delivery
 - [ ] Delayed rewards: tasks completed directly in Todoist (requires webhook from Todoist)
-- [ ] NATS JetStream replacing in-process bus (when multi-process pressure arrives)
+- [x] NATS JetStream bridge — durable `signals.>` and `feedback.>` streams; in-process bus stays the source of truth, every publish bridges out (#21, shipped)
 
 #### M1 add-on — Admin & ML Ops Console  *(fully shipped)*
 
@@ -220,8 +220,8 @@ Goal: tips are AI-generated from user context, not just raw Todoist tasks. Multi
 
 **Integrations & infra (carried from M1):**
 - [ ] Apple OAuth (#7)
-- [ ] NATS JetStream replacing in-process bus (#21)
-- [ ] Todoist sync via events (#22)
+- [x] NATS JetStream replacing in-process bus (#21) — adapter ships in `services/api/src/events/nats.ts`; in-proc bus is the producer, JetStream is the durable mirror
+- [x] Todoist sync via events (#22) — background scheduler in `services/api/src/signals/scheduler.ts` emits `signals.task.synced` every `TODOIST_SYNC_INTERVAL_MS`; on-demand fetch remains as freshness fallback
 - [ ] Event schema registry + protobuf CI gate (#54)
 - [ ] Per-user freshness SLAs for features (#61)
 - [ ] CI skeleton (#3), observability (#18), E2E tests (#20)