Match xattn_estimate internal logic by processing Q in chunks:
- Reduces peak memory for attn_scores tensor
- Enables testing 64K sequences without OOM
- All 5 test files pass (3.6K to 64K)
Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)
Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>
Test that xattn_estimate produces the same results as manually calling:
- flat_group_gemm_fuse_reshape
- softmax_fuse_block_sum
- find_blocks_chunked
Uses real KV cache data from results/kvcache/ directory.
Verifies density calculation matches between high-level API and kernels.
Generated with [Claude Code](https://claude.ai/code)
via [Happy](https://happy.engineering)
Co-Authored-By: Claude <noreply@anthropic.com>
Co-Authored-By: Happy <yesreply@happy.engineering>
