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/templates/caddy-compose.yml.j2

@@ -16,11 +16,11 @@ services:
     labels:
       glance.name: Caddy
       glance.icon: si:caddy
-      glance.url: https://thesatelliteoflove.com/
+      glance.url: https://{{ primary_domain }}/
       glance.description: Reverse proxy
     networks:
       default:
-        ipv4_address: 172.20.0.5
+        ipv4_address: {{ docker.hairpin_ip }}
 volumes:
   caddy_data:
   caddy_config:
@@ -28,4 +28,4 @@ volumes:
 networks:
   default:
     external: true
-    name: lava
+    name: {{ docker.network_name }}