Reorganize docker-compose stacks for better service grouping

Stack changes:
- Renamed media-extended.yml → media-management.yml (better clarity)
- Moved Plex from media → alternatives (Jellyfin is primary)
- Moved code-server from utilities → infrastructure
- Moved Sonarr, Radarr, Prowlarr from media → media-management
- Moved Calibre-web from media-management → media

New stack organization:
- media.yml (3): Jellyfin, Calibre-web, qBittorrent
- media-management.yml (13): All *arr apps, transcoders
- alternatives.yml (6): Plex, Portainer, Authentik
- infrastructure.yml (7): Added code-server
- utilities.yml (6): Removed code-server

Documentation updated:
- README.md: Updated stack descriptions
- services-overview.md: Updated service counts and locations
- All service docs: Updated file paths media-extended → media-management

docs/service-docs/mylar3.md

@@ -13,7 +13,7 @@
 
 **Category:** Comic Book Management  
 **Docker Image:** [linuxserver/mylar3](https://hub.docker.com/r/linuxserver/mylar3)  
-**Default Stack:** `media-extended.yml`  
+**Default Stack:** `media-management.yml`  
 **Web UI:** `http://SERVER_IP:8090`  
 **Ports:** 8090
 
@@ -49,7 +49,7 @@ Mylar3 is an automated comic book download manager. It's like Sonarr/Radarr but
 ### Directory Structure
 
 ```
-/opt/stacks/media-extended/mylar3/config/    # Configuration
+/opt/stacks/media-management/mylar3/config/    # Configuration
 /mnt/media/comics/                           # Comic library
 /mnt/downloads/                              # Downloads
 
@@ -90,7 +90,7 @@ mylar3:
     - PGID=1000
     - TZ=America/New_York
   volumes:
-    - /opt/stacks/media-extended/mylar3/config:/config
+    - /opt/stacks/media-management/mylar3/config:/config
     - /mnt/media/comics:/comics
     - /mnt/downloads:/downloads
   labels: