[widgets] Confirm annotation saves back to the player from TaskInfo

TaskInfo's onAnnotationChanged never called confirmAnnotationsSaved
back on the PreviewPlayer, so the player kept treating the first save
as still pending and silently dropped every annotation drawn afterwards
from a side panel. Align it with the other consumers (Task, Edit,
Playlist, ViewPlaylistModal) — await the dispatch, confirm on success,
restore on failure.

Port of upstream PR #2019.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: frankrousseau

src/components/sides/TaskInfo.vue

@@ -1119,17 +1119,22 @@ export default {
       this.currentPreviewDlPath = this.getOriginalDlPath()
     },
 
-    onAnnotationChanged({ preview, additions, deletions, updates }) {
+    async onAnnotationChanged({ preview, additions, deletions, updates }) {
       let taskId = this.task ? this.task.id : this.previousTaskId
       taskId = taskId || preview.task_id
-      if (taskId) {
-        this.updatePreviewAnnotation({
+      if (!taskId) return
+      const previewPlayer = this.$refs['preview-player']
+      try {
+        await this.updatePreviewAnnotation({
           taskId,
           preview,
           additions,
           deletions,
           updates
         })
+        previewPlayer?.confirmAnnotationsSaved()
+      } catch {
+        previewPlayer?.restoreFailedAnnotations()
       }
     },