Tab autocomplete broken for /add-dir directory arguments

Description

Tab autocomplete no longer works when typing directory names after /add-dir. Previously, I could type /add-dir followed by a partial repo/directory name, press Tab, and it would autocomplete the full path. Now I have to type the exact full name manually.

Steps to Reproduce

1. Open Claude Code
2. Type /add-dir followed by a partial directory name
3. Press Tab
4. Expected: Directory name autocompletes
5. Actual: Nothing happens — Tab triggers prompt suggestions instead

Context

This appears to be part of a broader Tab key regression introduced when Tab was reassigned to prompt suggestions/typeahead in v2.0.0+. Related issues:

• #9768 — Slash command tab autocomplete broken in VSCode extension
• #9338 — Filepath autocomplete affected by Tab reassignment
• #15848 — Bash ! mode tab completion broken

Environment

• macOS
• Claude Code CLI (terminal)