Class WasmKernel

WASM geometry kernel: ingests element geometry into a Rust ClashSession (flat arenas) and runs each rule's broad + narrow phase in Rust. Produces the same NarrowRecords as TsKernel — the orchestrator above is identical, so the two engines are differentially comparable.

Any per-element transform is baked into the world-space arena here, because the Rust kernel consumes world-space geometry directly (no transform path).