feat: add two-instance compare review UI (Phase 2)

- outline_sync.py: write compare results to /tmp/compare_results.json
  with full doc maps for parent-chain lookup during copy operations
- webui.py: /review page with remote-only, local-only, conflict tables;
  /review/content endpoint to fetch doc text from either instance;
  /review/apply endpoint for copy_to_local, copy_to_remote, keep_remote,
  keep_local, skip actions; "Compare Instances" button on dashboard;
  "Review Differences" link shown after compare completes
- entrypoint.sh: include local block in generated settings.json
- docker-compose.yml: pass LOCAL_OUTLINE_URL/TOKEN/HOST env vars
- deploy.yml: write LOCAL_* secrets to .env file

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -47,6 +47,7 @@ services:
       - OUTLINE_TOKEN=${OUTLINE_TOKEN}
       - LOCAL_OUTLINE_URL=${LOCAL_OUTLINE_URL:-}
       - LOCAL_OUTLINE_TOKEN=${LOCAL_OUTLINE_TOKEN:-}
+      - LOCAL_OUTLINE_HOST=${LOCAL_OUTLINE_HOST:-}
 
 volumes:
   tailscale-state: