Update keybindings to support new navigation commands and improve user
experience.
- Bind `Home` to `jump-first-col` and `End` to `jump-last-col` .
- Bind `PageUp` and `PageDown` to `page-scroll` .
- Update `o` keybinding from `add-record-row` to `open-record-row` .
- Bind `Tab` to `commit-and-advance-right` in editing mode.
Co-Authored-By: fiddlerwoaroof/git-smart-commit (unsloth/gemma-4-26B-A4B-it-GGUF:UD-Q5_K_XL)
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