Bus v2: resident WASM components with UI channels #181

Part of #173 (isolation plan). After 0.8.0.

The WASM component runner exists but is headless and run-once: Bus v1 has no UI, event or stream interface (elastos/wit/elastos-bus-v1.wit; elastos-compute/src/providers/component.rs). No shipped app uses it.

Done means

• Bus v2 defines resident components with event, stream and UI channels, still with no WASI, files or sockets.
• One first-party app runs its logic as a Bus v2 component with its UI as a render-only surface, and passes the hacked-Home suite.
• A migration order for the other apps is recorded here.