The horizontal lines on the side of the input prompt box may look nice but get in the way of users copying and pasting. We should remove the lines when not in alternate buffer mode to ease copying from the input prompt and provide a visual indication we are not in the app mode.

Current UI

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Proposed UI in alternate buffer mode

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The box should remain in alternate buffer mode where copy and paste needs custom handling anyway so there is no cost of the boarder and it might serve as a visual indication of switching between TUI and regular mode.