Run an Arora device in the browser.
The centerpiece is [BrowserRuntime], the reusable primitive that wires a
full [arora::Runtime] over an injected HAL, bridge, and data store and
exposes the JS-facing surface every browser device needs — a synchronous
step() plus Value↔JSON accessors on the store. [AroraRuntime] is the
bundled demo device built on it (in-process fakes + SimpleDataStore); each
downstream device ships its own thin #[wasm_bindgen] wrapper the same way.
It also carries a lower-level surface: [Engine] and [BehaviorTreeRunner]
load guest modules (header JSON + executable bytes) and run behavior trees
directly on the engine, hosting modules via the browser's native
WebAssembly runtime — see arora_engine::executor::browser.
This crate only carries non-trivial content when built for wasm32-*
targets. On the host it is an empty shim (deps are gated to wasm32) so it
can sit in the workspace and be verified by cargo package on publish
without pulling wasm-only deps into a host link.