CUB-231: Mosquitto MQTT broker setup on Pi Zero 2 W hub

- Install script for Mosquitto MQTT broker on Pi Zero 2 W (10.60.1.101)
- Persistence enabled with data stored in /var/lib/mosquitto/data/
- Topic ACL configuration for hub, sensor, mobile, and admin users
- systemd service with security hardening (NoNewPrivileges, ProtectSystem)
- Configuration files: mosquitto.conf, acl.conf
- Validation script to verify setup before deployment

validate-mosquitto.sh

@@ -0,0 +1,67 @@
+#!/bin/bash
+# validate-mosquitto.sh - Validate Mosquitto setup configuration
+# Run on Pi Zero 2 W to verify configuration before deployment
+
+set -e
+
+echo "=== Validating Mosquitto Configuration ==="
+
+# Check if configuration files exist
+echo "[CHECK 1/5] Verifying configuration files exist..."
+if [ -f /etc/mosquitto/conf.d/mosquitto.conf ]; then
+    echo "  ✓ mosquitto.conf exists"
+else
+    echo "  ✗ mosquitto.conf missing"
+    exit 1
+fi
+
+if [ -f /etc/mosquitto/acl/acl.conf ]; then
+    echo "  ✓ acl.conf exists"
+else
+    echo "  ✗ acl.conf missing"
+    exit 1
+fi
+
+# Check if mosquitto is installed
+echo "[CHECK 2/5] Verifying Mosquitto installation..."
+if command -v mosquitto &> /dev/null; then
+    echo "  ✓ mosquitto binary found"
+else
+    echo "  ✗ mosquitto binary not found"
+    exit 1
+fi
+
+# Validate configuration syntax
+echo "[CHECK 3/5] Validating configuration syntax..."
+if mosquitto -c /etc/mosquitto/conf.d/mosquitto.conf -t; then
+    echo "  ✓ Configuration syntax is valid"
+else
+    echo "  ✗ Configuration has syntax errors"
+    exit 1
+fi
+
+# Check persistence directory
+echo "[CHECK 4/5] Verifying persistence directory..."
+if [ -d /var/lib/mosquitto/data ]; then
+    echo "  ✓ Persistence directory exists"
+else
+    echo "  ✗ Persistence directory missing"
+    exit 1
+fi
+
+# Check ACL file permissions
+echo "[CHECK 5/5] Verifying file permissions..."
+if [ -f /etc/mosquitto/passwd ]; then
+    if [ "$(stat -c %a /etc/mosquitto/passwd)" = "600" ]; then
+        echo "  ✓ Password file has secure permissions (600)"
+    else
+        echo "  ⚠ Password file permissions should be 600"
+    fi
+else
+    echo "  ⚠ Password file not yet created (create with mosquitto_passwd)"
+fi
+
+echo ""
+echo "=== Validation Complete ==="
+echo "Configuration is ready for deployment to Pi Zero 2 W (10.60.1.101)"
+echo ""