thermite

Use Thermite, the generic ISA-portable Rust SIMD library, and its companion crates (special functions, autodiff Dual, Compensated double-double, SDF, geometry, FFI). Load when writing, reviewing, or debugging code that uses thermite/thermite-* crates, GenericVector/FloatVector/NumericVector trait bounds, the policy-based math library, masks, dispatch, slice iteration, or composite vector types. ALWAYS load this skill before working on Thermite's OWN source (contributing to / modifying the thermite/thermite-* crates themselves -- adding or changing a register op, backend, math kernel, polyfill, macro, or trait), and read references/development.md first in that case. Triggers: "write a SIMD kernel", "make this generic over vector types", "use thermite", "FloatVector bound", "autodiff with Dual", "compensated arithmetic", "SDF", thermite build/test errors, and any edit under crates/thermite*/src (register/vector/backend/math/element/macros).