Option to use letters (a/b/c) instead of numbers for dialog choices

What

Add an option to label interactive dialog choices (permission prompts, multiple-choice menus) with letters (a, b, c…) instead of numbers (1, 2, 3…).

Why

Number keys act as direct-select shortcuts in these dialogs. A common muscle-memory pattern is to arrow to the desired option and then press a key to "confirm." When that key is a number, it silently re-selects a different option by index rather than confirming the highlighted one — e.g. arrow down to option 2, press 1 intending "yes, go", and you've actually selected option 1. Lettered labels would break this collision between "confirm" habits and numeric indices, and avoid the ingrained "1 = yes" association some users carry from other tools.

Nice-to-have

A settings.json toggle (e.g. dialogOptionLabels: "letters" | "numbers") so it's opt-in.