fix(ui): scope tool-result to the current invocation

Address review feedback: the write Views derive their success card from
`toolResult`, but it wasn't cleared when a new invocation arrived (only the
in-app `successPR`/`successIssue` was reset on `toolInput` change). A completed
result from a previous invocation could briefly render a stale success card
over the next, still-deferred form.

Clear `toolResult` whenever a new `tool-input` notification arrives. The spec
guarantees `tool-input` precedes that invocation's `tool-result`, so this scopes
the result to the current invocation centrally in the hook — fixing all three
Views without per-app invocation keys.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: SamMorrowDrums

ui/src/hooks/useMcpApp.ts

@@ -69,6 +69,13 @@ export function useMcpApp({
       app.ontoolinput = async (input) => {
         const args = (input.arguments ?? {}) as Record<string, unknown>;
         setToolInput(args);
+        // A tool-input notification marks a new invocation, and the spec
+        // guarantees it is delivered before that invocation's tool-result.
+        // Drop any prior result so a completed result from a previous
+        // invocation can't leak into the new render (e.g. a stale success card
+        // showing over a fresh, still-deferred form). The current invocation's
+        // result, if any, arrives next via ontoolresult.
+        setToolResult(null);
         onToolInput?.(args);
       };
       app.onhostcontextchanged = (params) => {