feat(demo): add Homepage dashboard configuration files

- services.yaml: all 13 user-facing services organized by category
  with Pi-hole and Grafana widgets for live stats
- widgets.yaml: greeting, datetime, search, and Pi-hole glances widget
- bookmarks.yaml: developer resource links (GitHub, Stack Overflow,
  Docker Hub, Grafana Docs, InfluxDB Docs)
- settings.yaml: layout configuration (row style, column counts),
  Docker provider via socket proxy, and branding

Previously only docker.yaml existed, resulting in a bare-bones
dashboard with no widgets, bookmarks, or layout.

💘 Generated with Crush

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

demo/config/homepage/bookmarks.yaml

@@ -0,0 +1,24 @@
+---
+# Homepage Bookmarks
+
+- Developer Resources:
+    - GitHub:
+        - abbr: GH
+          href: https://github.com
+    - Stack Overflow:
+        - abbr: SO
+          href: https://stackoverflow.com
+    - Docker Hub:
+        - abbr: DH
+          href: https://hub.docker.com
+
+- Documentation:
+    - Docker Docs:
+        - abbr: DD
+          href: https://docs.docker.com
+    - Grafana Docs:
+        - abbr: GF
+          href: https://grafana.com/docs
+    - InfluxDB Docs:
+        - abbr: IF
+          href: https://docs.influxdata.com