[Bug] File reference autocomplete shows packages instead of project files

Bug Description
When using the @ mention feature to reference project files, no source files appear in the autocomplete suggestions — only packages and modules are shown, regardless of what filename is typed.

This issue occurs only in the Claude Code desktop app, not in the terminal CLI.

Steps to Reproduce

1. Open the Claude Code desktop app
2. Type @ followed by a source file name (e.g. @index.js)
3. Observe the autocomplete suggestions

Expected Behavior
Project source files matching the typed query should appear in the dropdown.

Actual Behavior
Only packages and external modules are listed. No project source files appear, even when the exact filename is typed. The same @ mention works correctly when using Claude Code in the terminal CLI.

Environment

• Claude Code version: 2.1.167 (issue first observed on 2.1.153)
• Platform: darwin-arm64 (macOS)
• Terminal: Apple Terminal
• Search status: OK (bundled)
• Feedback ID: 835dcc8a-6906-4147-9d11-5fd15f11711d

Errors

[]

Additional Context
/doctor shows all checks passing — search is OK with bundled ripgrep, Remote Control is enabled, and no errors are logged. The issue persisted after updating from 2.1.153 → 2.1.167 and fully restarting the desktop app.