Post-M9 milestone closing the loop on v1.0.0 prep.

Focus areas:

1. Pure-Rust completeness — close the last user-facing ffi-backend dependency (#179: nft_marker_gen .fset3 in Rust).
2. Validation tooling — Miri UB validation (#182) and a strict-clippy CI gate (#180) for high-confidence safety on the freshly-ported M9 code.
3. Performance — retire the deferred KPM perf target from #142 ("within 20% of C++ on pinball-demo"). Add a measuring bench first (#131), then optimize via SIMD (#132) and memory-layout tuning (#133) for Pyramid downsample. SIMD path covers AVX2 / SSE4.1 / wasm32.
4. Quality — raise M9 patch coverage to ≥90% (#177).
5. Examples — WASM browser examples for KPM/NFT (#161).
6. Maintenance — criterion 0.5 → 0.8 (#174).

Target: v0.8.0 release. Not blocking v1.0.0 by itself; sets the stage.