feat: add Pi monitoring stack with deployment scripts and architecture documentation

setup/pi-monitoring/stack.env.example

@@ -0,0 +1,39 @@
+# -----------------------------------------------------------------------------
+# Pi monitoring stack environment
+# Copy this file to stack.env and set real secrets before deployment.
+# -----------------------------------------------------------------------------
+
+# Compose project name
+COMPOSE_PROJECT_NAME=pi-monitoring
+
+# Persistent data root (place on SSD)
+OPS_ROOT=/srv/ops
+
+# Host timezone for containers
+TZ=America/New_York
+
+# Bind IP for published ports (0.0.0.0 = all interfaces)
+BIND_IP=0.0.0.0
+
+# Published service ports
+PORTAINER_HTTPS_PORT=9443
+PORTAINER_EDGE_PORT=8000
+GRAFANA_PORT=3000
+PROMETHEUS_PORT=9090
+UPTIME_KUMA_PORT=3001
+
+# Container images (override for pinning)
+PORTAINER_IMAGE=portainer/portainer-ce:latest
+GRAFANA_IMAGE=grafana/grafana-oss:latest
+PROMETHEUS_IMAGE=prom/prometheus:latest
+NODE_EXPORTER_IMAGE=prom/node-exporter:latest
+CADVISOR_IMAGE=gcr.io/cadvisor/cadvisor:latest
+UPTIME_KUMA_IMAGE=louislam/uptime-kuma:1
+
+# Grafana bootstrap admin credentials (change before deploy)
+GRAFANA_ADMIN_USER=admin
+GRAFANA_ADMIN_PASSWORD=replace-with-strong-password
+
+# Optional comma-separated plugin list for Grafana
+# Example: grafana-piechart-panel,grafana-clock-panel
+GRAFANA_PLUGINS=