fix: move Sablier middleware to dynamic configuration

Moved Sablier middleware from Docker labels to Traefik dynamic configuration
to fix "unknown plugin type: sablier" error. Traefik plugins can only be
used in dynamic file configuration, not in Docker labels.

Changes:
- Removed sablier-vert@file reference from Docker label middleware chain
- Added complete router definition to proxy/dynamic/vert-sablier.yaml
- Router includes full middleware chain: sablier-vert → vert-auth → compress
- Kept sablier.enable and sablier.group labels for Sablier service discovery

This allows Sablier to properly scale the container to zero while maintaining
the middleware chain order through file-based configuration.

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

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

vert/compose.yaml

@@ -20,7 +20,7 @@ services:
       - 'traefik.http.routers.${VERT_COMPOSE_PROJECT_NAME}-web-secure.entrypoints=web-secure'
       - 'traefik.http.middlewares.${VERT_COMPOSE_PROJECT_NAME}-auth.basicauth.users=${VERT_AUTH_USERS}'
       - 'traefik.http.middlewares.${VERT_COMPOSE_PROJECT_NAME}-web-secure-compress.compress=true'
-      - 'traefik.http.routers.${VERT_COMPOSE_PROJECT_NAME}-web-secure.middlewares=sablier-vert@file,${VERT_COMPOSE_PROJECT_NAME}-auth,${VERT_COMPOSE_PROJECT_NAME}-web-secure-compress'
+      - 'traefik.http.routers.${VERT_COMPOSE_PROJECT_NAME}-web-secure.middlewares=${VERT_COMPOSE_PROJECT_NAME}-auth,${VERT_COMPOSE_PROJECT_NAME}-web-secure-compress'
       - 'traefik.http.services.${VERT_COMPOSE_PROJECT_NAME}-web-secure.loadbalancer.server.port=80'
       - 'traefik.docker.network=${NETWORK_NAME}'
       - 'sablier.enable=${VERT_SABLIER_ENABLED}'