Agent apply-edits (Review / Apply / Undo)

ACE applies Agent file mutations through a Review modal and an undo stack.

Flow

1. Agent returns structured actions (create_file, apply_edit, write_full_file, delete_file).
2. With Auto-apply off, the proposed-change card shows Review & Apply.
3. Review modal:
   • Apply — every proposed change
   • Apply Selected — only checked rows
   • Cancel — no disk writes
4. After apply, open Monaco tabs reload from disk.
5. Undo restores the first pre-apply backup per file (not intermediate rewrites).

Reliability notes

• Undo backups are deduped by absolute path; the first content snapshot wins.
• Review buttons disable while an apply cycle is in flight.
• The Review overlay uses a high z-index so it is not trapped under the Assistant panel.

Sample

See desktop-ide/samples/phase3-apply-edits/.