Initial commit: docker-compose-config skill

Add skill for Docker Compose configuration management with:
- Multi-host environment structure with per-hostname overrides
- External volume mount patterns with env variable substitution
- Reverse proxy network configuration for SWAG integration
- Reference docs for examples and network topology

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

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

references/networks.md

@@ -0,0 +1,178 @@
+# Docker Compose Network Configuration
+
+## Network Topology
+
+```
+┌─────────────────────────────────────────────────────────────┐
+│                     reverse_proxy network                    │
+│  (attachable, shared across all projects)                   │
+│                                                             │
+│  ┌─────────┐  ┌─────────────┐  ┌─────────────┐            │
+│  │  SWAG   │  │ immich-srv  │  │  grist-srv  │  ...       │
+│  │ :443/80 │  │   :2283     │  │   :8484     │            │
+│  └─────────┘  └─────────────┘  └─────────────┘            │
+└─────────────────────────────────────────────────────────────┘
+         │              │                │
+         │              │                │
+    External        Internal         Internal
+    Traffic         Services         Services
+
+┌───────────────────┐    ┌───────────────────┐
+│   immich_default  │    │   grist_default   │
+│                   │    │                   │
+│  ┌─────────────┐  │    │  ┌─────────────┐  │
+│  │ immich-ml   │  │    │  │   grist     │  │
+│  └─────────────┘  │    │  └─────────────┘  │
+│  ┌─────────────┐  │    │  ┌─────────────┐  │
+│  │   redis     │  │    │  │  postgres   │  │
+│  └─────────────┘  │    │  └─────────────┘  │
+│  ┌─────────────┐  │    └───────────────────┘
+│  │  postgres   │  │
+│  └─────────────┘  │
+└───────────────────┘
+```
+
+## Network Types
+
+### 1. Project Default Network
+
+Automatically created by Compose. Services within same project communicate here.
+
+```yaml
+services:
+  app:
+    networks:
+      - default  # Implicit, connects to <project>_default
+
+  database:
+    networks:
+      - default  # Same network, can reach 'app' by service name
+```
+
+### 2. Reverse Proxy Network
+
+Shared external network for services needing reverse proxy access.
+
+```yaml
+services:
+  web-app:
+    networks:
+      - default        # Internal communication
+      - reverse_proxy  # Accessible by SWAG
+
+networks:
+  reverse_proxy:
+    name: reverse_proxy
+    attachable: true
+```
+
+### 3. Host Network Mode
+
+For services requiring direct host network access (e.g., Plex discovery):
+
+```yaml
+services:
+  plex:
+    network_mode: host
+    # No 'ports' mapping needed - uses host ports directly
+```
+
+## Network Configuration Patterns
+
+### Standard Web Service
+
+```yaml
+services:
+  myapp:
+    networks:
+      - default
+      - reverse_proxy
+
+networks:
+  reverse_proxy:
+    name: reverse_proxy
+    attachable: true
+```
+
+### Internal-Only Service (Database)
+
+```yaml
+services:
+  postgres:
+    networks:
+      - default
+    # No reverse_proxy - not externally accessible
+```
+
+### Service with Multiple Networks
+
+```yaml
+services:
+  api-gateway:
+    networks:
+      - default
+      - reverse_proxy
+      - monitoring
+
+networks:
+  reverse_proxy:
+    name: reverse_proxy
+    attachable: true
+  monitoring:
+    name: monitoring
+    attachable: true
+```
+
+## Service Discovery
+
+Services on the same network can reach each other by container name:
+
+```yaml
+services:
+  app:
+    container_name: myapp_server
+    environment:
+      REDIS_HOST: myapp_redis  # Uses container_name
+      DB_HOST: myapp_postgres
+
+  redis:
+    container_name: myapp_redis
+
+  database:
+    container_name: myapp_postgres
+```
+
+## External Network Declaration
+
+When connecting to pre-existing external networks:
+
+```yaml
+networks:
+  reverse_proxy:
+    external: true
+    name: reverse_proxy
+```
+
+vs creating if not exists:
+
+```yaml
+networks:
+  reverse_proxy:
+    name: reverse_proxy
+    attachable: true
+```
+
+## SWAG Proxy Configuration
+
+Services on `reverse_proxy` network are accessible to SWAG at their container name and internal port:
+
+| Service | Container Name | Internal URL |
+|---------|---------------|--------------|
+| Immich | immich_server | http://immich_server:2283 |
+| Grist | grist | http://grist:8484 |
+
+SWAG nginx config example:
+```nginx
+upstream_app immich_server;
+upstream_port 2283;
+```