[FEATURE] Custom commands completion view size

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When trying to find custom command Claude Code gives completion suggestion. However this list is only for 3-4 items - despite having much more space to use. Screenshot below:

<img width="869" height="580" alt="Image" src="https://github.com/user-attachments/assets/074268b4-9481-4c4b-9db8-ded6651abdc3" />

Proposed Solution

I'd like to have possibility to configure number of suggestions via config file (or be able to specify to use whole available height)

Alternative Solutions

I've tested in multiple terminal emulators (Wave Terminal, Ghostty, Terminal) on macOS to make sure it's Claude Code specific - not emulator one.

Priority

Medium - Would be very helpful

Feature Category

Configuration and settings

Use Case Example

1. Want to find custom command
2. Starting to type name custom command
3. Be able to see more results from completion suggestion without need to scroll in endless loop with arrows

Additional Context

_No response_