refactor: standardize service naming and migrate track to umami

Service Naming Standardization:
- Renamed all compose service names to use consistent `{project}_app` pattern
- awsm: `awesome` → `awesome_app`
- gotify: `gotify` → `gotify_app` (also updated container_name)
- proxy: `traefik` → `traefik_app`
- vpn: `wg-easy` → `vpn_app`
- sexy: `directus` → `sexy_api`, `frontend` → `sexy_frontend`

Track to Umami Migration:
- Removed track/ directory (legacy naming)
- Created umami/ directory with updated compose.yaml
- Service now named `umami_app` following naming convention
- Configuration unchanged: PostgreSQL backend, Redis caching, Traefik routing
- Uses TRACK_* environment variables for compatibility with arty.yml

Benefits:
- Consistent naming makes service identification easier across projects
- Aligns with container_name conventions ({PROJECT}_app pattern)
- Improves docker ps readability and service management
- Umami directory name matches actual product name

sexy/compose.yaml

@@ -1,5 +1,5 @@
 services:
-  directus:
+  sexy_api:
     image: ${SEXY_DIRECTUS_IMAGE}
     container_name: ${SEXY_COMPOSE_PROJECT_NAME}_api
     restart: unless-stopped
@@ -56,7 +56,7 @@ services:
       - 'traefik.http.services.${SEXY_COMPOSE_PROJECT_NAME}-api-web-secure.loadbalancer.server.port=8055'
       - 'traefik.docker.network=${NETWORK_NAME}'
 
-  frontend:
+  sexy_frontend:
     image: ${SEXY_FRONTEND_IMAGE}
     container_name: ${SEXY_COMPOSE_PROJECT_NAME}_frontend
     restart: unless-stopped