P9 complete: compiled kernels validated (byte-identical, 78-80 GSA samples/min/core), scaling report

Graviton3 c7g.8xlarge, 360 GSE165845 arrays: 360/360 GTCs identical between the Rust
kernels and the pure-Python paths; 1 worker 78-80 samples/min (pure Python 29.6).
Scaling 1->8 workers efficiency 0.87-0.90; above that the 125 MB/s gp3 disk caps the
run (~620 samples/min) and, on a RAM disk, a fixed per-worker start-up cost limits a
360-sample batch to efficiency 0.48 at 32 workers (K-025). Worker state is pickled once.
docs/validation/P9.md, result JSONs, guide/README/CHANGELOG updates.

README.md

@@ -22,8 +22,9 @@ differential-testing harness. Validation (`docs/validation/`):
 
 Commands: `simurg inspect`, `ingest`, `normalize`, `genotype`, `qc controls|samples|contamination|relatedness|loci|report|suggest-thresholds`,
 `gtc-to-vcf`, `export plink|bedgraph|finalreport|locus-summary`, `compare`. **User guide: `docs/user_guide.md`**;
-worked example: `examples/gsa_demo.sh`. Next (plan §18): P9 performance (compiled core), P10 packaging, then v2
-modules (cluster training, CN/LOH, PGx).
+worked example: `examples/gsa_demo.sh`. P9 (performance) is done: optional Rust kernels, byte-identical outputs,
+~80 GSA samples/min per server core (`docs/validation/P9.md`). Next (plan §18): P10 packaging, then v2 modules
+(cluster training, CN/LOH, PGx).
 
 ## Quick start