feat: add HTTP auth and Sablier scale-to-zero to VERT stack

Added authentication and scale-to-zero capabilities to VERT file converter service:

**Authentication**:
- Added HTTP Basic Auth middleware using VERT_AUTH_USERS
- Auth middleware applied to web-secure router
- Credentials configured via .env file (htpasswd format)

**Sablier Scale-to-Zero**:
- Added sablier.enable and sablier.group labels
- Created proxy/dynamic/vert-sablier.yaml with Sablier middleware config
- 1-hour session duration before automatic scale-down
- Ghost theme with custom display name
- Middleware chain: sablier-vert@file → auth → compress

**Configuration Updates**:
- Added VERT_SABLIER_ENABLED to arty.yml (default: true)
- Updated CLAUDE.md with auth and Sablier documentation
- Middleware order ensures Sablier wakes container before auth check

Infrastructure:
- Follows same pattern as Scrapy service for auth
- Dynamic Traefik configuration for Sablier plugin
- Container name: vert_app (referenced in Sablier config)

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

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

vert/compose.yaml

@@ -18,10 +18,13 @@ services:
       - 'traefik.http.routers.${VERT_COMPOSE_PROJECT_NAME}-web-secure.rule=Host(`${VERT_TRAEFIK_HOST}`)'
       - 'traefik.http.routers.${VERT_COMPOSE_PROJECT_NAME}-web-secure.tls.certresolver=resolver'
       - 'traefik.http.routers.${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=${VERT_COMPOSE_PROJECT_NAME}-web-secure-compress'
+      - 'traefik.http.routers.${VERT_COMPOSE_PROJECT_NAME}-web-secure.middlewares=sablier-vert@file,${VERT_COMPOSE_PROJECT_NAME}-auth,${VERT_COMPOSE_PROJECT_NAME}-web-secure-compress'
       - 'traefik.http.services.${VERT_COMPOSE_PROJECT_NAME}-web-secure.loadbalancer.server.port=80'
       - 'traefik.docker.network=${NETWORK_NAME}'
+      - 'sablier.enable=${VERT_SABLIER_ENABLED}'
+      - 'sablier.group=${VERT_COMPOSE_PROJECT_NAME}'
       - 'com.centurylinklabs.watchtower.enable=${WATCHTOWER_LABEL_ENABLE}'
 
 networks: