## Summary
- support Ctrl-b and Ctrl-f to move the cursor left and right in the
chat composer text area
- test Ctrl-b/Ctrl-f cursor movements
## Testing
- `just fmt`
- `just fix` *(fails: `let` expressions in this position are unstable)*
- `cargo test --all-features` *(fails: `let` expressions in this
position are unstable)*
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https://chatgpt.com/codex/tasks/task_i_689cbd1d7968832e876fff169891e486
