fix(ui-kit): make StateBoundary's onFailureNotify edge-triggered

StateBoundary's onFailureNotify effect was level-triggered instead of
edge-triggered: it re-fired on any render where isError stayed true and
onRetry/onFailureNotify (ordinary function props) changed identity, not
just on the false->true transition its own comment describes. Track the
previous isError value via a ref (mirroring the wasError pattern in
mcp-version-badge.tsx) so it only fires once per actual error-state entry,
and still re-fires correctly if the boundary leaves and re-enters error.

Closes #7436

Author: galuis116

apps/loopover-ui/src/components/site/state-views.test.tsx

@@ -138,3 +138,52 @@ describe("StateBoundary retry/refresh actions (#793 regression guard)", () => {
     expect(screen.getByText("content")).toBeTruthy();
   });
 });
+
+describe("StateBoundary onFailureNotify edge-triggered dedupe (#7436 regression)", () => {
+  it("fires onFailureNotify exactly once across re-renders while isError stays true, even as onRetry's identity changes", () => {
+    notifyApiFailure.mockClear();
+    // Each render passes a brand-new onRetry closure -- this mirrors the real app wrapper, which
+    // also constructs a fresh onFailureNotify arrow function on every render (#6506) -- so an
+    // unrelated re-render while the boundary is still in the error state must not re-notify.
+    const { rerender } = render(
+      <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+
+    for (let i = 0; i < 3; i++) {
+      rerender(
+        <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+          <div>content</div>
+        </StateBoundary>,
+      );
+    }
+
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+  });
+
+  it("fires again exactly once on a fresh false->true transition after leaving the error state", () => {
+    notifyApiFailure.mockClear();
+    const { rerender } = render(
+      <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+
+    rerender(
+      <StateBoundary isError={false} errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(1);
+
+    rerender(
+      <StateBoundary isError errorLabel="Widgets" onRetry={() => {}}>
+        <div>content</div>
+      </StateBoundary>,
+    );
+    expect(notifyApiFailure).toHaveBeenCalledTimes(2);
+  });
+});

packages/loopover-ui-kit/src/components/state-views.tsx

@@ -1,5 +1,5 @@
 import { Loader2, Inbox, AlertTriangle, RefreshCw, WifiOff } from "lucide-react";
-import { useEffect, type ReactNode } from "react";
+import { useEffect, useRef, type ReactNode } from "react";
 import { toast } from "sonner";
 
 import { cn } from "../utils";
@@ -264,9 +264,16 @@ export function StateBoundary({
       ? undefined
       : "The data source did not respond. Retry the request, or check back once the service has recovered.");
 
-  // When this boundary flips into the error state, surface a toast with Retry.
+  // When this boundary flips into the error state, surface a toast with Retry. Tracked via a ref
+  // (mirroring the `wasError` pattern in apps/loopover-ui/src/components/site/mcp-version-badge.tsx)
+  // so this only fires on the false->true edge, not on every re-render while isError stays true --
+  // onRetry/onFailureNotify are ordinary function props that get new identities on unrelated
+  // re-renders, and without edge detection those identity changes alone would re-run this effect.
+  const wasErrorRef = useRef(false);
   useEffect(() => {
-    if (isError && errorLabel) {
+    const enteredError = isError && !wasErrorRef.current;
+    wasErrorRef.current = Boolean(isError);
+    if (enteredError && errorLabel) {
       onFailureNotify?.({
         label: errorLabel,
         kind: errorKind ?? "network",