feat: complete variable management implementation and update documentation

- Update remaining Docker Compose templates with centralized variables
- Fix service tag isolation to deploy individual services only
- Update all README files with variable management architecture
- Document variable hierarchy in DEPLOYMENT_LEARNINGS.md
- Add comprehensive variable usage patterns to CLAUDE.md
- Standardize domain references using {{ subdomains.* }} pattern
- Replace hardcoded network names with {{ docker.network_name }}
- Update hairpinning configuration to use variables

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

roles/docker/tasks/main.yml

@@ -59,56 +59,24 @@
 # Deploy services by category for better organization and dependency management
 - name: Deploy infrastructure services
   import_tasks: infrastructure/main.yml
-  tags: 
-    - infrastructure
-    - caddy
-    - authentik
-    - dockge
+  tags: infrastructure
 
 - name: Deploy development services
   import_tasks: development/main.yml
-  tags:
-    - development
-    - gitea
-    - codeserver
-    - conduit
+  tags: development
 
 - name: Deploy media services
   import_tasks: media/main.yml
-  tags:
-    - media
-    - audiobookshelf
-    - calibre
-    - ghost-1
-    - pinchflat
-    - pinry
-    - hoarder
-    - karakeep
-    - manyfold
+  tags: media
 
 - name: Deploy productivity services
   import_tasks: productivity/main.yml
-  tags:
-    - productivity
-    - paperlessngx
-    - baikal
-    - syncthing
-    - mmdl
-    - heyform
-    - dawarich
-    - pingvin
+  tags: productivity
 
 - name: Deploy monitoring services
   import_tasks: monitoring/main.yml
-  tags:
-    - monitoring
-    - glance
-    - changedetection
-    - appriseapi
+  tags: monitoring
 
 - name: Deploy communication services
   import_tasks: communication/main.yml
-  tags:
-    - communication
-    - gotosocial
-    - postiz
+  tags: communication