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/stacks/monitoring/docker-compose.local.yml

@@ -0,0 +1,47 @@
+# Local Development Override for Monitoring Stack
+# Usage: docker compose -f docker-compose.yml -f docker-compose.local.yml up -d
+#
+# IMPORTANT: Must use LIST format labels like base config to prevent merging
+# Dictionary format + List format = Both remain (merged)
+# List format + List format = Properly merged/replaced
+#
+# This override file:
+# - Changes entrypoints from 'websecure' to 'web' (HTTP only for local dev)
+# - Removes TLS/Let's Encrypt configuration by NOT including those labels
+# - Keeps all other configuration from docker-compose.yml
+
+services:
+  portainer:
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.portainer.rule=Host(`portainer.${DOMAIN}`)"
+      - "traefik.http.routers.portainer.entrypoints=web"
+      - "traefik.http.routers.portainer.tls=false"
+      - "traefik.http.services.portainer.loadbalancer.server.port=9000"
+
+  prometheus:
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.prometheus.rule=Host(`prometheus.${DOMAIN}`)"
+      - "traefik.http.routers.prometheus.entrypoints=web"
+      - "traefik.http.routers.prometheus.tls=false"
+      - "traefik.http.routers.prometheus.middlewares=prometheus-auth@docker"
+      - "traefik.http.middlewares.prometheus-auth.basicauth.users=${PROMETHEUS_AUTH}"
+      - "traefik.http.services.prometheus.loadbalancer.server.port=9090"
+
+  grafana:
+    environment:
+      # Update root URL for HTTP
+      - GF_SERVER_ROOT_URL=http://grafana.${DOMAIN}:8081
+      - GF_SECURITY_ADMIN_USER=${GRAFANA_ADMIN_USER}
+      - GF_SECURITY_ADMIN_PASSWORD=${GRAFANA_ADMIN_PASSWORD}
+      - GF_USERS_ALLOW_SIGN_UP=false
+      - GF_INSTALL_PLUGINS=${GRAFANA_PLUGINS}
+      - GF_LOG_LEVEL=info
+      - GF_ANALYTICS_REPORTING_ENABLED=false
+    labels:
+      - "traefik.enable=true"
+      - "traefik.http.routers.grafana.rule=Host(`grafana.${DOMAIN}`)"
+      - "traefik.http.routers.grafana.entrypoints=web"
+      - "traefik.http.routers.grafana.tls=false"
+      - "traefik.http.services.grafana.loadbalancer.server.port=3000"