[BUG] Autocomplete highlight stuck on first custom command, doesn't update when typing built-in commands

Environment:

• Claude Code version: 2.0.33
• OS: macOS (Darwin 25.0.0)
• Terminal: Ghostty

Description:
When custom commands exist in ~/.claude/commands/, the autocomplete highlight gets stuck on the alphabetically first custom command and doesn't update when typing matches for built-in commands.

Steps to Reproduce:

1. Create any custom command in ~/.claude/commands/ that starts with 'a' (e.g., aaa-test.md)
2. In Claude Code terminal, type / to open autocomplete
3. Continue typing any built-in command (e.g., /exit, /hooks, /help)
4. Observe the autocomplete menu

Expected Behavior:

• As you type characters matching a command, the highlight should move to the matching command in the autocomplete list
• The highlight should update dynamically as you type

Actual Behavior:

• The moment / is typed, the highlight locks onto the first custom command alphabetically
• The autocomplete menu shows the correct filtered list of commands as you type
• BUT the highlight remains stuck on the first custom command (e.g., /aaa-test)
• This happens regardless of what you type (/exit, /hooks, etc.)
• Arrow keys are required to manually select the desired built-in command