feat(monitoring): add Prometheus/Grafana monitoring stack

- Add Grafana dashboard service (port 3000)
- Add Prometheus time-series database (port 9090)
- Add PVE Exporter for Proxmox metrics (port 9221)
- Deploy on VM 101 (monitoring-docker) at 192.168.2.114
- Configure scraping for Proxmox node 192.168.2.100
- Add docker-compose configurations for all services
- Add template files for sensitive credentials (pve.yml.template, .env.template)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

monitoring/pve-exporter/.env.template

@@ -0,0 +1 @@
+PVE_CONFIG_PATH=/path/to/your/pve.yml

monitoring/pve-exporter/docker-compose.yml

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+version: '3.8'
+services:
+  pve-exporter:
+    image: prompve/prometheus-pve-exporter:latest
+    container_name: pve-exporter
+    ports:
+      - "9221:9221"
+    restart: unless-stopped
+    volumes:
+      - ${PVE_CONFIG_PATH}:/etc/prometheus/pve.yml:ro
+    env_file:
+      - .env
+    labels:
+      org.label-schema.group: "monitoring"

monitoring/pve-exporter/pve.yml.template

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+default:
+    user: monitoring@pve
+    password: YOUR_MONITORING_USER_PASSWORD_HERE
+    verify_ssl: false