security: add HTTP Basic Auth to Netdata dashboard

Added HTTP Basic Authentication to secure the Netdata monitoring dashboard:
- Added basicauth middleware using shared AUTH_USERS credentials
- Protects sensitive infrastructure metrics from unauthorized access
- Uses same credentials as Scrapy and other protected services
- Maintains SSL/TLS encryption via Traefik

Security improvements:
- Dashboard now requires username/password
- Prevents public access to server metrics
- Infrastructure monitoring data protected
- Follows security best practices from Netdata documentation

Access requires credentials stored in AUTH_USERS environment variable.

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

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

netdata/compose.yaml

@@ -39,7 +39,8 @@ services:
       - 'traefik.http.routers.${NETDATA_COMPOSE_PROJECT_NAME}-web-secure.tls.certresolver=resolver'
       - 'traefik.http.routers.${NETDATA_COMPOSE_PROJECT_NAME}-web-secure.entrypoints=web-secure'
       - 'traefik.http.middlewares.${NETDATA_COMPOSE_PROJECT_NAME}-compress.compress=true'
-      - 'traefik.http.routers.${NETDATA_COMPOSE_PROJECT_NAME}-web-secure.middlewares=${NETDATA_COMPOSE_PROJECT_NAME}-compress,security-headers@file'
+      - 'traefik.http.middlewares.${NETDATA_COMPOSE_PROJECT_NAME}-auth.basicauth.users=${AUTH_USERS}'
+      - 'traefik.http.routers.${NETDATA_COMPOSE_PROJECT_NAME}-web-secure.middlewares=${NETDATA_COMPOSE_PROJECT_NAME}-auth,${NETDATA_COMPOSE_PROJECT_NAME}-compress,security-headers@file'
       # Service
       - 'traefik.http.services.${NETDATA_COMPOSE_PROJECT_NAME}.loadbalancer.server.port=19999'
       - 'traefik.docker.network=${NETWORK_NAME}'