[Feature Request] Make slash-command autocomplete dropdown height configurable

Bug Description
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Title: Make the slash-command / skill autocomplete dropdown height configurable

Type: Feature request

Summary:
When I type / to search for a slash command or skill, the autocomplete suggestion panel only shows a few rows at a time. With a large number of installed skills, this makes it hard to scan available options — I have to scroll through a small window instead of seeing the list at a glance.

Current behavior:
The dropdown renders a small fixed number of visible rows. There is no setting to control its height in settings.json, keybindings.json, environment variables, or CLI flags. The only way to see more results is to enlarge the terminal window or type more characters to narrow the list.

Requested behavior:
A way to configure the maximum number of visible rows in the autocomplete dropdown — for example a settings.json option such as autocompleteMaxRows (or having it expand to use more of the available terminal height by default).

Why it matters:
Users with many skills/commands installed benefit from seeing more matches at once, which speeds up discovery and selection. The current small panel is a friction point as a skill library grows.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.175
• Feedback ID: 4edfa78d-66d4-409a-95c1-4a51e3d348db

Errors

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