feat(proxy): add Traefik version tracking with notifications and dismissible UI warnings

- Add automated Traefik version checking job running weekly on Sundays
- Implement version detection from running containers and comparison with versions.json
- Add notifications across all channels (Email, Discord, Slack, Telegram, Pushover, Webhook) for outdated versions
- Create dismissible callout component with localStorage persistence
- Display cross-branch upgrade warnings (e.g., v3.5 -> v3.6) with changelog links
- Show patch update notifications within same branch
- Add warning icon that appears when callouts are dismissed
- Prevent duplicate notifications during proxy restart by adding restarting parameter
- Fix notification spam with transition-based logic for status changes
- Enable system email settings by default in development mode
- Track last saved/applied proxy settings to detect configuration drift

versions.json

@@ -15,5 +15,15 @@
         "sentinel": {
             "version": "0.0.16"
         }
+    },
+    "traefik": {
+        "v3.6": "3.6.0",
+        "v3.5": "3.5.6",
+        "v3.4": "3.4.5",
+        "v3.3": "3.3.7",
+        "v3.2": "3.2.5",
+        "v3.1": "3.1.7",
+        "v3.0": "3.0.4",
+        "v2.11": "2.11.31"
     }
 }