=== Heartbeat Debug Test ===

Test 1: Check device by MAC address
Response: {"success":true,"registered":true,"device":{"device_id":"TEST_DEVICE_001","device_name":"Test Kitchen Unit (Updated)","mac_address":"AA:BB:CC:DD:EE:FF","custom_serial_number":"TEST_KITCHEN_01","firmware_version":"v2.0.7.0-test","owner_name":null,"location_name":null,"hotspot_name":"TestWiFi_Guest","first_seen":"2025-11-07 22:02:47","last_seen":"2025-12-16 00:46:18","is_active":1}}

Test 2: Heartbeat with MAC address only
Response: {"success":true,"message":"Heartbeat recorded"}

Test 3: Direct database check
Device found in database:
  device_id: TEST_DEVICE_001
  mac_address: AA:BB:CC:DD:EE:FF
  custom_serial_number: TEST_KITCHEN_01

Test 4: Direct UPDATE test
Rows affected: 0

Test 5: Verify column names
Columns in devices table: device_id, device_name, mac_address, firmware_version, first_seen, last_seen, is_active, customer_id, site_location, health_score, performance_score, uptime_percentage, error_count, custom_serial_number, owner_id, location_id, hotspot_name, serial_number_changed_at, metadata_last_updated, owner_name, location_name