feat: project-scoped Docker image prune, conflict fix, deploy toggle, access list picker

- Image prune only removes images matching project image refs, skips active instances
- Add ListImagesByRef and RemoveImage to Docker client
- Fix 409 conflict: use listProjects instead of duplicate POST
- Add "Deploy immediately" toggle to Quick Deploy (off by default)
- Replace raw access list ID with EntityPicker on project edit form
- Trigger proxy resync on access list change
- Fix stage form layout: single responsive row
- Fix empty port default on project creation
- Improve inspect error message for remote Docker

web/src/lib/i18n/en.json

@@ -250,6 +250,12 @@
     "appearance": "Appearance",
     "staleThreshold": "Stale threshold (days)",
     "staleThresholdHelp": "Containers inactive for longer than this will be flagged as stale.",
+    "dockerCleanup": "Docker Image Cleanup",
+    "dockerCleanupHelp": "Remove unused Docker images belonging to your projects. Only images not used by active instances are removed.",
+    "pruneImages": "Prune Unused Images",
+    "pruning": "Pruning...",
+    "pruneResult": "Removed {count} images, reclaimed {mb} MB",
+    "pruneFailed": "Failed to prune images",
     "proxyProvider": "Proxy Provider",
     "proxyProviderHelp": "Select how reverse proxy routes are managed for deployed containers.",
     "proxyNone": "None",