Support ripple delete for timeline clips and add a return-to-recording action

[huangwenxuangod]

i make sth with this feature to improve my daily using experience

Summary

The editor currently allows deleting clips from the settings panel, but the keyboard deletion flow for timeline clips has been inconsistent. Also, once users enter the editor, there is no quick way to return to the recording UI.

Problems

1. Timeline clips cannot be reliably deleted with Backspace / Delete in the same way users expect from modern editors.
2. Deleting a clip should support a ripple-delete workflow:
   • remove the selected clip
   • remove or adjust child regions within that clip range
   • shift all following timeline items left by the deleted duration
   • keep timeline timing aligned
3. After deleting a clip, selection should move to the next clip, or fall back to the previous one.
4. There is no convenient action in the editor chrome to return to the recording UI.

Expected behavior

• When a timeline clip is selected and the timeline/editor is focused, pressing Backspace or Delete should delete that clip.
• Clip deletion should behave like ripple delete:
  • remove the clip
  • shift subsequent clips forward
  • shift zoom, annotation, speed, and audio regions by the same duration
  • trim or remove regions overlapping the deleted time range as needed
• If the deleted clip was selected, selection should move to the next clip, or the previous clip if there is no next one.
• Add a lightweight “Return to recording” action in the editor header.

Notes

This should keep existing project behavior as intact as possible and prefer minimal changes over broad refactors.