perf(canvas): 画布媒体 - 优化媒体加载、播放器与节点交互 (#357)

Merge origin/main at fb089b2 and retain canvas media performance, player layout, and interaction updates.

Co-authored-by: ddCat <2695092045@qq.com>

web/src/lib/canvas/canvas-generation-task-sync.ts

@@ -66,6 +66,15 @@ export function videoMetadata(video: UploadedFile): CanvasNodeMetadata {
         bytes: video.bytes,
         mimeType: video.mimeType || "video/mp4",
         durationMs: video.durationMs,
+        hasAudio: video.hasAudio,
+        videoPreview: video.preview ? {
+            content: video.preview.url,
+            storageKey: video.preview.storageKey,
+            width: video.preview.width,
+            height: video.preview.height,
+            bytes: video.preview.bytes,
+            mimeType: video.preview.mimeType,
+        } : undefined,
         errorDetails: undefined,
         generationErrorCode: undefined,
         resourceReloadAvailable: undefined,