- Add ResolveNWayCollisions function for deterministic global resolution
- Replace pairwise ScoreCollisions approach with content-hash-based sorting
- Implement helper functions: groupCollisionsByID, deduplicateVersionsByContentHash, extractNumber
- Update importer.go to use new resolution flow
- Add applyNWayResolution to create remapped issues
- Export UpdateReferences for use by importer
- Add comprehensive tests for N-way collision resolution
- All tests pass including TestTwoCloneCollision
This enables proper convergence for N-way (3+) collision scenarios where
multiple clones create issues with the same ID but different content.
The algorithm groups all versions, deduplicates by content, sorts by hash,
and assigns sequential IDs deterministically.
Amp-Thread-ID: https://ampcode.com/threads/T-3e649e13-792c-4fb5-a342-58fa805eb517
Co-authored-by: Amp <amp@ampcode.com>