fix: 修复摄像头无法正常启动，以及关闭摄像头会导致后端崩溃的问题

server/src/Controllers/VideoStreamController.cs

@@ -146,7 +146,7 @@ public class VideoStreamController : ControllerBase
     }
 
     [HttpPost("SetVideoStreamEnable")]
-    [ProducesResponseType(typeof(object), StatusCodes.Status200OK)]
+    [ProducesResponseType(typeof(string), StatusCodes.Status200OK)]
     [ProducesResponseType(typeof(string), StatusCodes.Status500InternalServerError)]
     public async Task<IActionResult> SetVideoStreamEnable(bool enable)
     {
@@ -155,7 +155,7 @@ public class VideoStreamController : ControllerBase
             var boardId = TryGetBoardId().OrThrow(() => new ArgumentException("Board ID is required"));
 
             await _videoStreamService.SetVideoStreamEnableAsync(boardId.ToString(), enable);
-            return Ok($"HDMI transmission for board {boardId} disabled.");
+            return Ok($"HDMI transmission for board {boardId} {enable.ToString()}.");
         }
         catch (Exception ex)
         {