Add MQTT publish request and response models, and implement publish route

- Introduced MQTTPublishRequest and MQTTPublishResponse models for handling MQTT message publishing.
- Implemented a new POST route for publishing MQTT messages, including error handling and logging.
- Enhanced the StandaloneAutoRecorder with improved logging during manual recording start.
- Updated the frontend to include an MQTT Debug Panel for better monitoring and debugging capabilities.

camera-management-api/usda_vision_system/api/models.py

@@ -334,3 +334,21 @@ class SuccessResponse(BaseModel):
     message: str
     data: Optional[Dict[str, Any]] = None
     timestamp: str = Field(default_factory=lambda: datetime.now().isoformat())
+
+
+class MQTTPublishRequest(BaseModel):
+    """MQTT publish request model"""
+
+    topic: str = Field(..., description="MQTT topic to publish to")
+    payload: str = Field(..., description="Message payload")
+    qos: int = Field(default=0, ge=0, le=2, description="Quality of Service level (0-2)")
+    retain: bool = Field(default=False, description="Whether to retain the message")
+
+
+class MQTTPublishResponse(BaseModel):
+    """MQTT publish response model"""
+
+    success: bool
+    message: str
+    topic: str
+    payload: str

camera-management-api/usda_vision_system/api/routes/mqtt_routes.py

@@ -7,7 +7,7 @@ from typing import Dict
 from fastapi import FastAPI, HTTPException, Query
 from ...core.state_manager import StateManager
 from ...mqtt.client import MQTTClient
-from ..models import MQTTStatusResponse, MQTTEventsHistoryResponse, MQTTEventResponse
+from ..models import MQTTStatusResponse, MQTTEventsHistoryResponse, MQTTEventResponse, MQTTPublishRequest, MQTTPublishResponse
 
 
 def register_mqtt_routes(
@@ -70,3 +70,33 @@ def register_mqtt_routes(
             logger.error(f"Error getting MQTT events: {e}")
             raise HTTPException(status_code=500, detail=str(e))
 
+    @app.post("/mqtt/publish", response_model=MQTTPublishResponse)
+    async def publish_mqtt_message(request: MQTTPublishRequest):
+        """Publish an MQTT message (for testing/debugging)"""
+        try:
+            if not mqtt_client.is_connected():
+                raise HTTPException(status_code=503, detail="MQTT client is not connected")
+            
+            success = mqtt_client.publish_message(
+                topic=request.topic,
+                payload=request.payload,
+                qos=request.qos,
+                retain=request.retain
+            )
+            
+            if success:
+                logger.info(f"Published MQTT message: {request.topic} -> {request.payload}")
+                return MQTTPublishResponse(
+                    success=True,
+                    message=f"Message published successfully to {request.topic}",
+                    topic=request.topic,
+                    payload=request.payload
+                )
+            else:
+                raise HTTPException(status_code=500, detail="Failed to publish MQTT message")
+        except HTTPException:
+            raise
+        except Exception as e:
+            logger.error(f"Error publishing MQTT message: {e}")
+            raise HTTPException(status_code=500, detail=str(e))
+