A push to `dev` now becomes a live demo, and a failed build never takes the
demo down.
- Four tables (pipeline_runs, pipeline_steps, releases, app_runtimes) and their
migration; alembic upgrade/downgrade/check all clean.
- DeliveryService implements DeliveryHooks: on_app_created provisions the demo
port + host + first build (idempotently); on_branch_pushed queues a run for
`dev` and supersedes older *queued* runs, leaving a running one alone.
- The 8-step pipeline. Blue/green is real: the replacement starts on a staging
port, is healthchecked, and only then does the route move — then the previous
container is stopped. A failure removes the replacement, releases its port and
leaves the old container serving.
- The demo port ledger is the DATABASE, not the router adapters' in-memory maps:
the API and the delivery worker are separate processes.
- Runs are claimed with a conditional UPDATE, so two workers never build the
same run.
- Live logs are batched (1 event / 500 ms, 200 lines) and redacted as a whole
tail — per-chunk redaction misses a secret split across pipe reads, and the
*stored* tail leaked until this was fixed.
- delivery worker: drain the queue, then poll remotes for pushes made outside
the engine.
- 7 routes; reads need membership, actions need projects.manage and are audited.
Tests: 415 API (+21, 1 docker-marked skipped); ruff, mypy, alembic check clean.
Report: docs/plan/reports/agent-3-phase-3.md
