refactor(test): share cron isolated agent fixtures

src/cron/isolated-agent.mocks.ts

@@ -0,0 +1,15 @@
+import { vi } from "vitest";
+
+vi.mock("../agents/pi-embedded.js", () => ({
+  abortEmbeddedPiRun: vi.fn().mockReturnValue(false),
+  runEmbeddedPiAgent: vi.fn(),
+  resolveEmbeddedSessionLane: (key: string) => `session:${key.trim() || "main"}`,
+}));
+
+vi.mock("../agents/model-catalog.js", () => ({
+  loadModelCatalog: vi.fn(),
+}));
+
+vi.mock("../agents/subagent-announce.js", () => ({
+  runSubagentAnnounceFlow: vi.fn(),
+}));