Refine .env.example files across all stacks

- Streamline variable organization and formatting
- Reduce redundant comments and improve clarity
- Maintain all required variables for each stack

docker-compose/monitoring/.env.example

@@ -1,12 +1,10 @@
 # Monitoring Stack Environment Variables
-# These variables are used for Prometheus, Grafana, Uptime Kuma, etc.
 
-# Base Configuration
-DOMAIN=
-
-# User Configuration
+TZ=
 PUID=
 PGID=
+SERVER_IP=
+SERVER_HOSTNAME=
+DOMAIN=
 
-# Grafana Configuration
 GRAFANA_ADMIN_PASSWORD=