fix(hub): always send interrupt notice when card finalize fails

If StreamingAgentCard.finish cannot patch the live card, plain-text fallback
can still succeed with partial answer text. Interrupt is terminal — always
emit the explicit 已中断 notice when the card path failed so teachers see the
abort. Harden the integration assertion with waitFor.

hub/test/integration/trigger.test.ts

@@ -1611,7 +1611,9 @@ describe("trigger full lifecycle (integration)", () => {
       expect(runs[0]?.status).toBe("CANCELED");
     });
     expect(patch).toHaveBeenCalled();
-    expect(rt.sentTexts).toContain("已中断当前运行。");
+    await vi.waitFor(() => {
+      expect(rt.sentTexts).toContain("已中断当前运行。");
+    });
   });
 
   it("denies interrupt when the operator lacks agent.cancel permission", async () => {