fix(apps): address review of app-rendered elicitations

Eight findings from the Copilot review, all accepted.

Ownership across connections was the substantive one, in three parts. A
mid-session transport close reaches teardown only through
`clearAndAnnouncePendingPeerRequests`, whose emptiness check looked at the
native queues alone — so a lone app elicitation survived a dropped connection
with its modal still open; the check now counts the active set too. The web
bridge factory resolves its client at call time, so an entry queued by a
replaced `InspectorClient` could rebuild against the *next* one and answer
through a different server; the host now drops every entry synchronously on
the swap (`AppElicitationController.failAll`) rather than racing core's
awaited teardown. And the request id was only monotonic within one client, so
each replacement client's first request was `app-elicitation-1` — settling
that id could resolve the wrong server's request. It now carries a
per-instance prefix.

Result validation now parses the whole value with `ElicitResultSchema` before
the requested-schema check, instead of inspecting `action` by hand: a
`{ action: "decline", content: { x: {} } }` used to pass, though the standard
result permits only primitives and string arrays in `content`.

The dialog's accessible name now includes the request id and the prompt — two
concurrent elicitations can be for the same app URI, and the previous name
made those indistinguishable, which is what the comment beside it claimed to
prevent.

`observeAppCapabilities` takes a minimal structural `onmessage` contract
(generic over the message type, since a handler typed for a narrower message
is not assignable to one typed for `unknown`), removing the double cast at the
call site.

`smoke:web:elicit` now fails on an uncaught page error after a successful
drive, and captures the async half of that class off the console channel, as
its two sibling smokes do — it could otherwise print OK over a broken bundle.

Adds the tests each fix needs, including the two the review asked for
directly: that `advertiseElicitation` reaches the `AppBridge` constructor, and
that it is absent by default.

Signed-off-by: cliffhall <cliff@futurescale.com>

clients/web/src/App.tsx

@@ -850,6 +850,20 @@ function App() {
     },
     [appElicitationController],
   );
+  // Request ownership must not cross connections. `elicitationBridgeFactory`
+  // resolves its client at call time, so an entry queued by a previous
+  // InspectorClient would otherwise be able to rebuild against the NEXT one and
+  // read (or answer) through a different server. Core aborts its own pending
+  // app requests during teardown, but that teardown is awaited asynchronously
+  // while the swap here is synchronous — so drop them on the swap instead of
+  // racing it. The one client alive at a time owns every live entry.
+  useEffect(() => {
+    return () => {
+      appElicitationController.failAll(
+        new Error("Connection replaced before the app answered"),
+      );
+    };
+  }, [appElicitationController, inspectorClient]);
 
   const [managedToolsState, setManagedToolsState] =
     useState<ManagedToolsState | null>(null);