feat: add monitoring dashboard (Prometheus + Grafana + Umami + Admin)

Phase 1: Infrastructure
- Add docker/prometheus/prometheus.yml with scrape configs for all services
- Add docker/grafana/provisioning for auto-configured datasources
- Add docker/grafana/dashboards (system-overview, backends-docker)
- Update docker-compose.macmini.yml with monitoring services:
  - prometheus, grafana, node-exporter, cadvisor
  - postgres-exporter, redis-exporter, umami
- Add grafana.mana.how and analytics.mana.how to Caddyfile

Phase 2: Backend Metrics
- Create packages/shared-nestjs-metrics with:
  - MetricsModule (auto /metrics endpoint)
  - MetricsService (Counter, Histogram, Gauge helpers)
  - MetricsMiddleware (auto HTTP request tracking)

Phase 3: Umami Web Analytics
- Add Umami tracking scripts to all landing pages
- Add Umami tracking scripts to all web apps
- Create scripts/mac-mini/setup-umami-db.sh

Phase 4: Admin Dashboard (ManaCore Web)
- Add admin routes: /admin, /admin/users, /admin/system
- Create StatCard, QuickLinks, UserTable components
- Add Admin link to navigation

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker/caddy/Caddyfile.production

@@ -0,0 +1,90 @@
+# ManaCore Production Reverse Proxy
+# Domain: mana.how
+# Server: 46.224.108.214
+#
+# Deploy to: ~/Caddyfile on production server
+# Reload with: docker exec caddy caddy reload --config /etc/caddy/Caddyfile
+
+# ============================================
+# Auth Service
+# ============================================
+auth.mana.how {
+    reverse_proxy localhost:3001
+}
+
+# ============================================
+# ManaCore Dashboard (Main)
+# ============================================
+mana.how {
+    reverse_proxy localhost:5173
+}
+
+www.mana.how {
+    redir https://mana.how{uri} permanent
+}
+
+# ============================================
+# Chat App
+# ============================================
+chat.mana.how {
+    reverse_proxy localhost:3000
+}
+
+chat-api.mana.how {
+    reverse_proxy localhost:3002
+}
+
+# ============================================
+# Todo App
+# ============================================
+todo.mana.how {
+    reverse_proxy localhost:5188
+}
+
+todo-api.mana.how {
+    reverse_proxy localhost:3018
+}
+
+# ============================================
+# Calendar App
+# ============================================
+calendar.mana.how {
+    reverse_proxy localhost:5186
+}
+
+calendar-api.mana.how {
+    reverse_proxy localhost:3016
+}
+
+# ============================================
+# Clock App
+# ============================================
+clock.mana.how {
+    reverse_proxy localhost:5187
+}
+
+clock-api.mana.how {
+    reverse_proxy localhost:3017
+}
+
+# ============================================
+# Contacts App
+# ============================================
+contacts.mana.how {
+    reverse_proxy localhost:5184
+}
+
+contacts-api.mana.how {
+    reverse_proxy localhost:3015
+}
+
+# ============================================
+# Monitoring & Analytics
+# ============================================
+grafana.mana.how {
+    reverse_proxy localhost:3100
+}
+
+analytics.mana.how {
+    reverse_proxy localhost:3200
+}