Rust ports of the hot paths found by profiling: fused per-locus GenCall calling and scoring, BAF/LRR, libm maps with CPython math semantics, both nearest-neighbour searches of the normalization fit, and the BPM LocusEntry parser. Address coverage is memoised per IDAT layout. SIMURG_PURE_PYTHON=1 forces the pure paths. On the Pi: genotype_sample 3.4 s -> 1.1 s, 36-sample GSA run 131 s -> 46 s, BPM read 4x faster; 36 GSA + 6 Omni2.5 GTCs and QC tables byte-identical to the pure path; tests/unit/test_core_kernels.py checks every kernel on edge cases. bench/profile_genotype.py, bench/scaling.py, cloud task p9 (thread scaling). Co-Authored-By: Claude Opus 5.5 <[email protected]> Claude-Session: https://claude.ai/code/session_01814GKVzZVL3FuF3DeiZXhv