fix: prevent Traefik restart loops and improve Docker registry login

Registry Login Fixes:
- Filter out service names (minio, redis) from registry URL extraction
- Only recognize actual registry URLs (with TLD or port)
- Preserve port numbers in registry URLs (e.g. git.michaelschiemer.de:5000)
- Better error messages for failed logins

Traefik Restart Loop Prevention:
- Set traefik_auto_restart default to false in traefik role
- Add traefik_auto_restart, traefik_ssl_restart, gitea_auto_restart to staging vars
- Add guard to fix-gitea-traefik-connection.yml restart task
- Add guard and deprecation warning to update-gitea-traefik-service.yml

This ensures that:
- CI/CD pipelines won't cause Traefik restart loops
- Staging environment uses same safe defaults as production
- Deprecated playbooks fail by default unless explicitly enabled
- Only actual Docker registries are used for login, not service names

deployment/ansible/roles/traefik/defaults/main.yml

@@ -18,7 +18,7 @@ traefik_check_health: true
 traefik_show_status: true
 
 # Config Deployment
-traefik_auto_restart: true  # Automatically restart after config deployment
+traefik_auto_restart: false  # Automatically restart after config deployment (default: false to prevent restart loops)
 
 # Logs Configuration
 traefik_logs_tail: 100