- Replace per-tile page lookup with per-element lookup in load_tile
- Remove page_ok gate and scalar fallback in launch_paged_decode_mma
- Unified path works for any page_size (L1-cached when page_size >= BC)
- HBM BW: 12% → 73%, decode throughput: 2,250 → 2,606 tok/s (B=32)
- Scales to 5,232 tok/s at B=128 (2.54x vs torch native)
- Merge 3 duplicated dispatch blocks into single attn_dispatchers.cuh
- Merge compute_num_splits from attn_utils.cuh into dispatcher header
- All dim3 grid/block declarations and <<<>>> launches are single-line
- Production .cu files (35-42 loc) only handle torch wrapping + pybind11
- Test files include dispatcher header directly, removing all #ifndef ASTRAI_NO_MMA duplication