- Add scalar paged prefill kernel mirroring split-Q MMA indexing for sm<80 - Wire scalar path into dispatch_paged_prefill under ASTRAI_NO_MMA - Fix paged decode scalar causal mask dropping all kv>0 for decode
- Add scalar paged prefill kernel mirroring split-Q MMA indexing for sm<80 - Wire scalar path into dispatch_paged_prefill under ASTRAI_NO_MMA - Fix paged decode scalar causal mask dropping all kv>0 for decode