file autocomplete doesn't work for uninitialized git submodules

Environment:

• macOS Darwin 25.2.0
• Claude Code (latest)
• ripgrep installed (/opt/homebrew/bin/rg)

Steps to reproduce:

1. Have .gitmodules defining a submodule
2. Have the submodule directory with full .git folder (cloned separately, not via git submodule update --init)
3. Directory is NOT in .gitignore
4. Try @submodule/file.json autocomplete → doesn't suggest files

Expected: Files in untracked/uninitialized submodule directories should be indexed if not gitignored

Actual: No file suggestions until running git submodule update --init

Root cause: Filesystem traversal treats nested .git directories as repository boundaries and excludes them from indexing

Workaround: Initialize submodule properly or use custom fileSuggestion with git ls-files