fix(custom-widgets): address review findings

apps/nextjs/src/app/api/assistant/chat/custom-widget-authoring-context.spec.ts

@@ -15,6 +15,15 @@ const userMessage = (text: string): UIMessage => ({
 });
 
 describe("Custom Widget authoring context", () => {
+  test("refunds a focused discovery claim when the tool call fails", () => {
+    const controller = createCustomWidgetDiscoveryPhaseController();
+
+    expect(controller.claim("customWidget_getComponents")).toBe(true);
+    expect(controller.claim("customWidget_getComponents")).toBe(false);
+    controller.observeFailure("customWidget_getComponents");
+    expect(controller.claim("customWidget_getComponents")).toBe(true);
+  });
+
   test.each([
     "Create a custom widget for these fixtures",
     "Create custom widgets for these services",

apps/nextjs/src/app/api/assistant/chat/custom-widget-authoring-context.ts

@@ -42,7 +42,17 @@ export const createCustomWidgetDiscoveryPhaseController = (limit = maxFocusedCom
       if (toolName === "customWidget_createFromPreview" && typeof result?.id === "string") reset();
     },
     observeFailure(toolName: string) {
-      if (toolName === "customWidget_validateTemplate" || toolName === "customWidget_previewCreate") reset();
+      if (toolName === "customWidget_validateTemplate" || toolName === "customWidget_previewCreate") {
+        reset();
+        return;
+      }
+      if (customWidgetContextToolBudgets[toolName] === undefined) return;
+      const used = calls.get(toolName) ?? 0;
+      if (used <= 1) {
+        calls.delete(toolName);
+        return;
+      }
+      calls.set(toolName, used - 1);
     },
   };
 };