fix: Resolve Cargo.lock hashbrown duplicate entries

Restore Cargo.lock from upstream/main and regenerate to avoid hashbrown
version conflicts (0.15.5 vs 0.16.0). This ensures CI dependency checks pass
while maintaining all required dependencies for du caching feature.

Changes:
- Restored base Cargo.lock from upstream/main
- Regenerated to include du dependencies (ahash, bincode, parking_lot, rayon)
- Result: Only 2 hashbrown versions (0.14.5, 0.15.4) instead of 3
- All 61 du tests passing
- Clippy clean

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: quantum-encoding