fix: Gitea Traefik routing and connection pool optimization

- Remove middleware reference from Gitea Traefik labels (caused routing issues)
- Optimize Gitea connection pool settings (MAX_IDLE_CONNS=30, authentication_timeout=180s)
- Add explicit service reference in Traefik labels
- Fix intermittent 504 timeouts by improving PostgreSQL connection handling

Fixes Gitea unreachability via git.michaelschiemer.de

deployment/docs/guides/code-change-workflow.md

@@ -284,7 +284,7 @@ https://git.michaelschiemer.de/michael/michaelschiemer/actions
 ssh deploy@94.16.110.151
 
 # Container-Status prüfen
-cd ~/deployment/stacks/application
+cd ~/deployment/stacks/production
 docker compose ps
 
 # Logs ansehen
@@ -489,7 +489,7 @@ git push origin main
 ssh deploy@94.16.110.151
 
 # Logs prüfen
-cd ~/deployment/stacks/application
+cd ~/deployment/stacks/production
 docker compose logs app
 
 # Manuell rollback
@@ -535,7 +535,7 @@ git push origin feature/my-feature
 # → https://git.michaelschiemer.de/michael/michaelschiemer/actions
 
 # Application-Status prüfen
-ssh deploy@94.16.110.151 "cd ~/deployment/stacks/application && docker compose ps"
+ssh deploy@94.16.110.151 "cd ~/deployment/stacks/production && docker compose ps"
 ```
 
 ### Deployment-Zeit