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/media/.env.example

@@ -1,12 +1,10 @@
 # Media Stack Environment Variables
-# These variables are used for Jellyfin, Calibre-web, etc.
 
-# Base Configuration
-DOMAIN=
 TZ=
-
-# User Configuration
 PUID=
+PGID=
+SERVER_IP=
+SERVER_HOSTNAME=
+DOMAIN=
 
-# Directory Configuration
 MEDIA_DIR=