observability configs: loki delete_request_store, prometheus targets, grafana root URL

- loki: recent releases require compactor.delete_request_store when
  retention is enabled (was crash-looping on start)
- prometheus: scrape targets carried legacy dankclaw.local names with
  URL schemes (invalid); point at published LAN ports and the gitea
  quadlet's published port instead
- grafana: GF_SERVER_ROOT_URL to the canonical HTTPS name
- tests: 3 new seams for the deployed observability configs

shared/prometheus/prometheus.yml

@@ -21,10 +21,10 @@ scrape_configs:
     static_configs:
       - targets: ["192.168.0.235:9100"]
 
-  # Gitea metrics
+  # Gitea metrics (quadlet on an isolated network; use the published LAN port)
   - job_name: "gitea"
     static_configs:
-      - targets: ["gitea:3000"]
+      - targets: ["192.168.0.143:3000"]
     metrics_path: "/metrics"
 
   # Grafana metrics
@@ -45,12 +45,11 @@ scrape_configs:
     static_configs:
       - targets: ["comfyui:8188"]
 
-  # Blackbox-style probes for service up/down
+  # Blackbox-style probes for service up/down (published LAN ports;
+  # gitea and comfyui are covered by their own jobs above)
   - job_name: "services"
     metrics_path: "/"
     static_configs:
       - targets:
-          - "http://search.dankclaw.local"
-          - "http://chat.dankclaw.local"
-          - "http://gitea.dankclaw.local"
-          - "http://comfyui.dankclaw.local"
+          - "192.168.0.143:8081"   # SearXNG (via the Gluetun tunnel)
+          - "192.168.0.143:3005"   # OpenWebUI