Align the coordinator with the master PLAN.md (CTX-00, CTX-04) and harden
process startup.
- CTX-00: freeze docs/api-contract.md as the v1 source of truth for the
Go coordinator and Python worker.
- CTX-04: worker registry — workers table (migration 0002), domain.Worker,
RegisterWorker use case, WorkerRepository, and POST /workers/register.
- Contract alignment: claim uses `capabilities` (was `workloads`),
COORDINATOR_TOKEN env (WORKER_AUTH_TOKEN kept as fallback), and
GET /health now reports database readiness (503 when the DB is down).
- Logging: logs are teed to stdout and an optional rotated file (LOG_FILE)
via lumberjack, so they survive a container rebuild.
- Startup resilience: the initial DB connection is retried with backoff,
so the coordinator waits for Postgres to boot instead of crash-looping.
Two ways to exercise every endpoint, both living in the repo rather than in a
personal Postman workspace:
- scripts/smoke.sh walks the full lifecycle and asserts each status, exiting
non-zero on the first surprise, so it works in CI as well as by hand;
- api/requests.http drives the same calls from an editor's REST client, with
later requests reusing ids captured from earlier responses. It doubles as
API documentation for the worker author.
The script claims until it sees its own job's chunks instead of assuming an
empty queue: a shared development database usually holds pending tasks from
earlier runs, and it takes the attempt number from the claim response, since a
task requeued after an expired lease comes back with attempt 2 or 3.
Note for whoever extends the validation cases: Go matches JSON field names
case-insensitively, so "worker_ID" is accepted as "worker_id". Only a genuinely
unknown key trips DisallowUnknownFields.