feat(demo): restore ArchiveBox, TubeArchivist, Atuin and fix all service configs

Restore 3 services that were previously removed due to health issues,
bringing the stack to 16 services. Add companion services (Elasticsearch,
Redis) required by TubeArchivist.

Key changes:
- Add ArchiveBox with proper health check and admin credentials
- Add TubeArchivist with ta-redis and ta-elasticsearch companions
- Add Atuin server with correct `server start` command and TCP health check
- Fix Wakapi health check to use /app/healthcheck binary
- Add Grafana provisioning bind mount for datasources/dashboards
- Add Homepage config bind mount for docker.yaml
- Fix Docker Socket Proxy label (remove unreachable localhost:4005 href)
- Fix credentials: INFLUXDB_ADMIN_USER and TA_USERNAME → admin
- Fix Grafana datasources.yml user to match
- Fix homepage/docker.yaml to contain Docker provider config
- Add all missing env vars (TA_PASSWORD, ELASTIC_PASSWORD, ES_JAVA_OPTS, etc.)
- Remove Pi-hole port 53 bindings (DNS not needed for demo)
- Bump template version to 2.0

💘 Generated with Crush

Assisted-by: GLM-5.1 via Crush <crush@charm.land>

demo/config/grafana/datasources.yml

@@ -8,7 +8,7 @@ datasources:
     access: proxy
     url: http://influxdb:8086
     database: demo_metrics
-    user: demo_admin
+    user: admin
     password: demo_password
     isDefault: true
     jsonData: