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- Add notifications across all channels (Email, Discord, Slack, Telegram, Pushover, Webhook) for outdated versions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

app/Data/ServerMetadata.php

@@ -10,6 +10,8 @@ class ServerMetadata extends Data
 {
     public function __construct(
         public ?ProxyTypes $type,
-        public ?ProxyStatus $status
+        public ?ProxyStatus $status,
+        public ?string $last_saved_settings = null,
+        public ?string $last_applied_settings = null
     ) {}
 }