Add maintenance API endpoints

docs/dashboard-esp32s3.md

@@ -47,11 +47,15 @@ All grounds remain common.
 ## API endpoints consumed
 
 Minimum dashboard MVP:
+- GET /api/v1/health
 - GET /api/v1/status
 - POST /api/v1/relay/set
 
 Potential later use:
+- GET /api/v1/capabilities
 - GET /api/v1/config
+- GET /api/v1/config/export
+- POST /api/v1/config/import
 - POST /api/v1/config/save
 - POST /api/v1/temps/scan
 - POST /api/v1/temps/assign
@@ -120,10 +124,11 @@ Then interactive:
 
 1. Dashboard boots.
 2. Connects to cargo ESP32 AP.
-3. Polls GET /api/v1/status.
-4. Shows disconnected state until valid JSON is received.
-5. Updates dashboard on a fixed interval.
-6. Relay buttons call POST /api/v1/relay/set.
+3. Checks GET /api/v1/health.
+4. Polls GET /api/v1/status.
+5. Shows disconnected state until valid JSON is received.
+6. Updates dashboard on a fixed interval.
+7. Relay buttons call POST /api/v1/relay/set.
 
 ## Polling Guidance