feat: infrastructure dashboard (Homepage) generated from the service registry

playbooks/dashboard.yml deploys Homepage as a second compose stack on the
monitoring LXC (CT 155) next to Uptime Kuma and renders its config from
homelab_services: one tile per service, link to its UI, grouped by Proxmox
node. Adding a service to the registry is enough — no second service list.

- new registry consumer: playbooks/dashboard.yml + playbooks/templates/homepage-*.j2
- homelab_dashboard_* vars in group_vars/all/services.yml (top-level, like
  homelab_reverse_proxy_*); image pinned by digest, floating tag needs an
  explicit -e dashboard_allow_floating_tag=true
- bootstrap-dashboard-pve-token.yml: read-only homepage@pve!dashboard token
  (PVEAuditor) for the Proxmox widget, secret in the root .env as DASHBOARD_PVE_*
- Makefile: dashboard, dry-dashboard, bootstrap-dashboard-token
- container binds the LAN address only (192.168.1.30:8082), not published via Caddy
- docs: architecture.md Monitoring section, plan.md active task, consumer lists

Deployed to CT 155 on 2026-09-03: container healthy, http://192.168.1.30:8082/
returns 200, `make dashboard` idempotent, `make validate` and `make lint` green.
Pending operator steps: `make bootstrap-dashboard-token` (blocked in the agent
session as credential creation) and an Uptime Kuma status page with slug homelab.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KbuZrUoevfBgCpf5DCF4DG

ansible/playbooks/templates/homepage-widgets.yaml.j2

@@ -0,0 +1,18 @@
+#jinja2: trim_blocks: True, lstrip_blocks: True
+# {{ ansible_managed }}
+# Верхняя панель Homepage. Рендерится playbooks/dashboard.yml.
+- datetime:
+    text_size: xl
+    format:
+      timeStyle: short
+      dateStyle: short
+- resources:
+    label: monitoring CT
+    cpu: true
+    memory: true
+    disk: /
+- uptimekuma:
+    # Требует опубликованной Status Page в Uptime Kuma с этим slug
+    # (мониторы и статус-страницы Kuma живут только в её UI).
+    url: http://{{ dash_bind }}:3001
+    slug: {{ homelab_dashboard_kuma_slug | default('homelab') }}