修复: 进度条seek完成后同步currentPositionMs防止抖动

- 重置isSeeking前先将currentPositionMs同步到seek目标位置
- 防止轮询循环在player追上之前用旧位置覆盖显示

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

app/src/main/kotlin/com/example/myapplication/screens/VideoPlayerScreen.kt

@@ -1047,6 +1047,9 @@ fun VideoPlayerScreen(
                                 LaunchedEffect(seekCompletedVersion) {
                                     if (seekCompletedVersion > 0) {
                                         delay(300)
+                                        // Sync currentPositionMs to the seek target before resuming polling
+                                        // to prevent a visual jump when player position hasn't caught up yet
+                                        currentPositionMs = (progress * totalDurationMs).toLong()
                                         isSeeking = false
                                     }
                                 }