Detects and cleans up files that are now centralized:
- SOUL.md: removed (now global at ~/.config/mosaic/SOUL.md)
- CLAUDE.md: replaced with thin pointer to global AGENTS.md
- AGENTS.md: stale load-order sections stripped, project content preserved
Supports --dry-run, --all (scan ~/src/*), and per-project paths.
Creates .mosaic-bak backups before any modification.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
