feat: add HTTP Basic Auth to paint service

Protected paint.pivoine.art with HTTP Basic Auth using shared AUTH_USERS
credentials, matching the security setup of scrapy and other protected services.

Changes:
- Added basicauth middleware with AUTH_USERS variable
- Added compression middleware
- Updated router middlewares chain to include auth, compress, and security headers

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

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

paint/compose.yaml

@@ -15,11 +15,13 @@ services:
       - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web.middlewares=${PAINT_COMPOSE_PROJECT_NAME}-redirect-web-secure'
       - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web.rule=Host(`${PAINT_TRAEFIK_HOST}`)'
       - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web.entrypoints=web'
-      # HTTPS router
+      # HTTPS router with auth
       - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web-secure.rule=Host(`${PAINT_TRAEFIK_HOST}`)'
       - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web-secure.tls.certresolver=resolver'
       - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web-secure.entrypoints=web-secure'
-      - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web-secure.middlewares=security-headers@file'
+      - 'traefik.http.middlewares.${PAINT_COMPOSE_PROJECT_NAME}-auth.basicauth.users=${AUTH_USERS}'
+      - 'traefik.http.middlewares.${PAINT_COMPOSE_PROJECT_NAME}-web-secure-compress.compress=true'
+      - 'traefik.http.routers.${PAINT_COMPOSE_PROJECT_NAME}-web-secure.middlewares=${PAINT_COMPOSE_PROJECT_NAME}-auth,${PAINT_COMPOSE_PROJECT_NAME}-web-secure-compress,security-headers@file'
       # Service
       - 'traefik.http.services.${PAINT_COMPOSE_PROJECT_NAME}-web-secure.loadbalancer.server.port=80'
       - 'traefik.docker.network=${NETWORK_NAME}'