feat(phase3): PWA, auto-discovery, bookmarklet, multi-tab sync

- PWA: manifest, service worker (cache-first static, network-first API),
  offline page, install prompt banner
- Auto-discovery: Docker socket + Traefik API scanning, approval UI
- Quick-add bookmarklet: popup-based add page, favicon auto-detect
- Multi-tab sync: BroadcastChannel for theme + data changes
- i18n translations for all new strings (EN/RU)

src/lib/i18n/en.json

@@ -215,6 +215,26 @@
   "admin.perm_none": "No permissions configured.",
   "admin.perm_search_placeholder": "Type to search...",
 
+  "admin.discovery_title": "Service Discovery",
+  "admin.discovery_description": "Scan Docker containers and Traefik routers to automatically discover running services and register them as apps.",
+  "admin.discovery_scan": "Scan for Services",
+  "admin.discovery_scanning": "Scanning...",
+  "admin.discovery_approve": "Approve Selected",
+  "admin.discovery_approving": "Approving...",
+  "admin.discovery_source": "Source",
+  "admin.discovery_status": "Status",
+  "admin.discovery_source_docker": "Docker",
+  "admin.discovery_source_traefik": "Traefik",
+  "admin.discovery_already_registered": "Already registered",
+  "admin.discovery_new": "New",
+  "admin.discovery_no_results": "No services discovered. Check your Docker socket path or Traefik API URL.",
+  "admin.discovery_config": "Service Discovery Configuration",
+  "admin.discovery_config_description": "Configure Docker and Traefik endpoints for automatic service discovery. These settings are used by the Discovery panel below.",
+  "admin.discovery_docker_socket": "Docker Socket Path",
+  "admin.discovery_docker_socket_hint": "Path to Docker socket (e.g. /var/run/docker.sock). Set via DOCKER_SOCKET_PATH env var.",
+  "admin.discovery_traefik_url": "Traefik API URL",
+  "admin.discovery_traefik_url_hint": "Traefik dashboard API base URL (e.g. http://traefik:8080). Set via TRAEFIK_API_URL env var.",
+
   "admin.import_export_title": "Import / Export",
   "admin.import_export_description": "Export all data (apps, boards, groups, settings) as JSON, or import from a previously exported file.",
   "admin.export_section": "Export Data",
@@ -291,5 +311,26 @@
   "settings.language": "Language",
   "settings.save": "Save Preferences",
   "settings.saving": "Saving...",
-  "settings.saved": "Preferences saved!"
+  "settings.saved": "Preferences saved!",
+
+  "offline.title": "You're Offline",
+  "offline.description": "It looks like you've lost your internet connection. Check your network and try again.",
+  "offline.retry": "Retry",
+
+  "install.title": "Install App",
+  "install.description": "Add Web App Launcher to your home screen for quick access.",
+  "install.button": "Install",
+  "install.dismiss": "Dismiss install prompt",
+
+  "settings.bookmarklet_title": "Quick-Add Bookmarklet",
+  "settings.bookmarklet_instructions": "Drag the button below to your browser's bookmarks bar. When visiting any web page, click it to quickly add that site to your App Launcher.",
+  "settings.bookmarklet_drag": "Add to Launcher",
+  "settings.bookmarklet_drag_hint": "Drag this to your bookmarks bar",
+  "settings.bookmarklet_show_code": "Show bookmarklet code",
+
+  "app.quick_add_title": "Quick Add App",
+  "app.quick_add_description": "Review the details below and save to add this app to your launcher.",
+  "app.quick_add_success": "App added successfully!",
+  "app.quick_add_view_apps": "View Apps",
+  "app.quick_add_close": "Close Window"
 }