Module encode 

WebAssembly binary-encoding primitives — the shared byte layer beneath both the browser WASM-JIT tier (super::region_jit) and the direct AOT backend ([super::module]).

Hand-rolled LEB128 + section/instruction encoders (no external wasm crate): the same routines wasm_jit.rs proved correct against wasmi and real V8. Nothing here depends on the wasm-jit feature — byte emission is target- and feature-independent; only running the emitted modules (super::region_jit) touches wasmi/js_sys.