* fix(react): close App on useApp unmount; relax late-handler guard for re-registration
useApp's effect cleanup now closes the App (and its transport) instead
of only flipping a `mounted` flag. Under React StrictMode dev
double-invoke, the abandoned first instance's PostMessageTransport
otherwise keeps a window `message` listener and receives every host
postMessage alongside the second instance.
The late-handler guard from #629 now tracks `_everHadListener` per
event and only flags the *first* registration of a one-shot event
post-handshake. Re-registration (React useEffect cleanup + re-add on
dep change) of an event that had a pre-connect handler is silent,
including under `strict: true`.
* feat(app-bridge): warn on second ui/initialize
If a View double-mounts (e.g. React StrictMode in dev) without closing
the previous App, AppBridge now logs a console.warn when it receives a
second ui/initialize. Behavior is unchanged — it still responds and the
latest appInfo/appCapabilities replace the previous values — this is
purely a diagnostic for host implementers.