feat(docker-watcher): phase 5 - registry client & poller

Gitea registry client with tag listing and pattern matching, cron-based
polling scheduler with first-poll safety, poll state persistence.
DeployTriggerer interface for decoupled deploy triggering.

PLAN.md

@@ -261,12 +261,12 @@ Core infrastructure — store, config import, Docker client, NPM client.
 5. **Docker client** — connect to socket, pull image, inspect image, list/start/stop/remove containers, manage networks
 6. **NPM client** — authenticate (JWT), create/update/delete proxy hosts, list existing hosts
 
-### Phase 2: Detection & Deployment
+### Phase 2: Detection & Deployment (Registry & Poller ✅)
 
 The core loop — detecting new images and deploying them.
 
-8. **Registry client** — Gitea registry API: list tags for an image, detect new tags
-9. **Poller** — periodic check for new tags matching configured patterns
+8. **Registry client** ✅ — Gitea registry API: list tags for an image, detect new tags
+9. **Poller** ✅ — periodic check for new tags matching configured patterns
 10. **Secret webhook handler** — UUID-based URL, receives image push notifications, auto-creates unknown projects
 11. **Deployer** — orchestrate: pull → start container → NPM proxy → health check
 12. **Multi-instance support** — multiple versions per project/stage, tag-based subdomains, max_instances limit