The sole crate permitted to contain audited kernel unsafe islands.

Every future unsafe kernel must be feature-gated, carry a SAFETY: comment, and retain a bit-identical safe scalar fallback.

Frankentorch boundary

This Phase-0 scaffold intentionally has no frankentorch dependency: it does not yet expose a kernel facade that consumes one. Add each dependency only alongside a real facade API and its scalar fallback; do not predeclare a machine-local or otherwise unused substrate dependency.

Permanent integer-kernel law

A route cannot become dispatchable until [selftest::run_selftest] proves its all-extreme reduction at every model-specific census binding row against an independent i64 oracle: the U8S8 envelope (255 * 127 * K, the ceiling for a future unsigned-activation VNNI route) on the checked scalar path, and the S8S8 kernel contract (±127 * 127 * K) through the real [int8::dot_i32] on every available tier with scalar equality. Every native tier, Q4 unpack path, codec convolution, verifier, and batched variant extends that same surface before it may be selected.