Verify attention backend functions are actually callable before marking them available. Falls back to PyTorch SDPA instead of calling None. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Verify attention backend functions are actually callable before marking them available. Falls back to PyTorch SDPA instead of calling None. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>