Fold the sentinel into the scraper and drop the sentinel service (BL-0046)

The stall watchdog now runs inside the scraper (ScraperService.checkStalls,
every 30 s from the work loop): same rule as before, one checkpoint-safe
restart, quarantine on the second stall, missing checkpoint is no evidence,
and paused time no longer counts. Stalls are recorded as scraper incidents
(failure.kind 'stall'). The private /api/recovery endpoint is gone.

Dropped with the service: reader/scraper-unreachable incidents (supervisor
and Docker handle crashes; the health page shows "Scraper: unreachable"),
duplicate job-failure incidents and the unused /metrics endpoint.
The stack is now reader + scraper (+ optional peer-gateway).
The supervisor test moved to runtime/test (npm run test:runtime stays).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

vision/server-peering.md

@@ -107,7 +107,7 @@ Suggested NoDB files (names are design targets, not existing files): reader-owne
 3. **Read-only publisher:** optional gateway, bounded approved-only catalog/manifest/blob endpoints, quota enforcement, read-only mounts. Test that unshared, partially downloaded, deleted, and revoked content cannot be listed or fetched—even by guessed IDs or stale manifests. Verify no user data fields or raw source URLs appear on the wire.
 4. **Consumer browsing:** local-server proxy and reader UI with peer status, search, details, selection preview, and queue permission checks. No browser-to-peer credentials or direct requests.
 5. **Scraper transfer lane:** chapter/page checkpoints, range resume, hashes, local throttles, source-aware deduplication, and existing atomic chapter publication. Test corruption, interrupted transfer, stale revision, out-of-space, repeated queue submission, and preservation of current jobs.
-6. **Observability and operations:** per-peer health, bytes, throttling, grant expiry warnings, queue stalls, and safe retry controls. Sentinel may report a dead gateway or stuck transfer but must not renew trust, broaden a share, or bypass a quota. Document backup/restore and key-rotation runbooks.
+6. **Observability and operations:** per-peer health, bytes, throttling, grant expiry warnings, queue stalls, and safe retry controls. Service health may report a dead gateway or stuck transfer but must not renew trust, broaden a share, or bypass a quota. Document backup/restore and key-rotation runbooks.
 7. **Local then VM pilot:** three local Compose instances with distinct data directories; pair A↔B and A↔C, exercise every direction combination, and transfer a few admin-approved test chapters. Verify disabling B does not affect C, no account/progress exchange, and quota isolation. Only then deploy the optional service on the VM's private network. Leave existing reader/scraper ports and active downloads undisturbed during the pilot.
 
 **Ship gate:** a fresh unpaired server sees nothing; a paired server with serving off or no granted manga sees an empty catalog; an expired/revoked peer cannot list or fetch; invitations cannot be reused; disabling one direction or peer leaves unrelated peers intact; quotas survive restart; a receiver can resume and publish one chapter without duplicates; and its browser never receives the grant token or any private key. The feature remains disabled by default until those gates pass.