Add Navigation Key Commands, and Asterisk to ID files that have been edited but not saved

### Description

I like this coding app tremendously, but a few quality of life improvements that I have noticed and would like to recommend.

1. Navigation: Would it be possible to add the ability to move between open files using command+option+left or right arrow to switch tabs, much like a browser.
2. Identify Unsaved File: Would it be possible to add an asterisk (*) to the end of the file name in the tab to indicate that is has been changed but not yet saved? Helpful for knowing what has been edited and needs to be saved.
3. Disable Mac Auto-text: Would it be possible to disable, or provide a checkbox/option to disable, the auto text inherent on a mac? Such as adding a period after double spacing and other things? This has been annoying while coding.

Thank you!
~Agnapot

### Alternatives Considered

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### Additional Context

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### Screenshots

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No files, tests, or entry points are identified. Start by clarifying whether these three requests should be separate issues, then locate the tab navigation, file-tab title or unsaved-state handling, and macOS text-input settings; done requires agreed behavior and tests for each selected request.

Written by the indexing model from the issue text.