feat: publish versioned agent images — compose should use image: not build: (#429)

- Generated compose now uses `image: ghcr.io/disinto/{agents,edge}` instead
  of `build:` directives; `disinto init --build` restores local-build mode
- Add VOLUME declarations to agents, reproduce, and edge Dockerfiles
- Add CI pipeline (.woodpecker/publish-images.yml) to build and push images
  to ghcr.io/disinto on tag events
- Mount projects/, .env, and state/ into agents container for runtime config
- Skip pre-build binary download when compose uses registry images

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

docker/agents/Dockerfile

@@ -28,6 +28,9 @@ RUN chmod +x /entrypoint.sh
 
 # Entrypoint runs polling loop directly, dropping to agent user via gosu.
 # All scripts execute as the agent user (UID 1000) while preserving env vars.
+VOLUME /home/agent/data
+VOLUME /home/agent/repos
+
 WORKDIR /home/agent/disinto
 
 ENTRYPOINT ["/entrypoint.sh"]