Adds `crates/wasm-actor/` (swactor-wasm-actor), which embeds wasmtime-sandboxed
Wasm instances inside regular swactor actors. Messages flow as raw bytes through
the guest ↔ host contract (alloc/handle exports, swactor.send import). The host
drains an outbox after each handle call and routes messages via ctx.send().
Includes 3 no_std guest modules (echo, double, silent) and 7 integration tests
covering roundtrip delivery, binary fidelity, multi-send, error cases, engine
sharing, and native↔wasm interop.
Authored by Claude, lovingly guided by Zachery Aaron Shores-Chmielewski
60ee2d1a2c
