Fullscreen mode: slash-command autocomplete hard-capped at 5 visible rows, doesn't scale with terminal height like inline mode

Environment

• Claude Code version: 2.1.211 (latest at time of filing)
• Platform: macOS (Darwin 25.5.0), Ghostty
• Renderer: default fullscreen (alternate-screen) mode

Describe the bug

In fullscreen mode, the slash-command / @-mention autocomplete popup shows at most 5 rows, regardless of terminal height. In a ~90-row terminal window the list still shows only 5 commands, so browsing the command list means arrow-scrolling through a tiny window while the rest of the screen sits empty.

The 2.1.132 changelog entry — "Fixed slash command autocomplete popup being capped at ~3–5 visible commands instead of scaling with terminal height" — only applies to the inline (non-alternate-screen) renderer. The fullscreen overlay path never got the scaling.

Both code paths live in the same suggestion-list component. Its visible-height budget is computed as (minified, from the 2.1.211 binary):

let {rows: c, columns: u} = Dr(); // terminal size
let d = o /* overlay */ ? fv_    // fv_ = 5, hard-coded constant
      : Math.max(1, Math.min(Math.max(6, Math.floor(c / 2)), c - 3));

So inline mode scales to ~half the terminal height (min 6), while fullscreen mode short-circuits to the constant 5.

Expected behavior

The fullscreen overlay list should scale with available terminal height like the inline renderer does (e.g. reuse the max(6, floor(rows/2)) budget, or at least offer a setting). With CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1 the list scales as expected — but that gives up mouse support and the rest of the fullscreen UI just to see the command list.

Steps to reproduce

1. Open Claude Code 2.1.211 in a tall terminal window (50+ rows), default fullscreen mode.
2. Type /.
3. The autocomplete popup shows only 5 commands.
4. Relaunch with CLAUDE_CODE_DISABLE_ALTERNATE_SCREEN=1 and repeat — the list now scales with terminal height.