## What changed
- Add a bounded redo stack for complete composer drafts, including paste payloads and image attachments. `Ctrl+R` now reapplies the last undone edit in Vim normal mode, while new edits clear stale redo history.
- Add the configurable `vim_normal.redo` action to the keymap schema and picker. Preserve reverse prompt-history search in Vim insert mode and non-Vim mode, and honor explicitly configured bindings.
- Keep pending edit snapshots outside the shared undo/redo byte budget so canceled commands cannot evict committed history.
## Testing
- Cover grouped edits, Vim searches, direct draft changes, history limits, empty redo stacks, and custom or unbound shortcuts.
GitOrigin-RevId: 0cf5bb376ff865ddc0a77705dcb322ef6b57b3a3