feat(video): 事务化切换与前端统一编排，增强视频输入格式支持

- 后端：切换事务+transition_id，/stream/mode 返回 switching/transition_id 与实际 codec

- 事件：新增 mode_switching/mode_ready，config/webrtc_ready/mode_changed 关联事务

- 编码/格式：扩展 NV21/NV16/NV24/RGB/BGR 输入与转换链路，RKMPP direct input 优化

- 前端：useVideoSession 统一切换，失败回退真实切回 MJPEG，菜单格式同步修复

- 清理：useVideoStream 降级为 MJPEG-only

src/msd/monitor.rs

@@ -120,7 +120,10 @@ impl MsdHealthMonitor {
         // Log with throttling (always log if error type changed)
         let throttle_key = format!("msd_{}", error_code);
         if error_changed || self.throttler.should_log(&throttle_key) {
-            warn!("MSD error: {} (code: {}, count: {})", reason, error_code, count);
+            warn!(
+                "MSD error: {} (code: {}, count: {})",
+                reason, error_code, count
+            );
         }
 
         // Update last error code