feat(FN-4485): complete Step 4-5 orphan rescue and audit paths

Fusion-Task-Id: FN-4485
Fusion-Task-Lineage: 034088dc-ebc4-4e12-8314-39419d41b23f

packages/engine/src/__tests__/reliability-interactions/branch-recovery-orphan-rescue.test.ts

@@ -0,0 +1,63 @@
+import { EventEmitter } from "node:events";
+import { beforeEach, describe, expect, it, vi } from "vitest";
+import type { TaskStore } from "@fusion/core";
+import { SelfHealingManager } from "../../self-healing.js";
+import * as branchConflicts from "../../branch-conflicts.js";
+import * as worktreePool from "../../worktree-pool.js";
+
+function createStore(): TaskStore & EventEmitter {
+  const emitter = new EventEmitter() as TaskStore & EventEmitter;
+  (emitter as any).getSettings = vi.fn().mockResolvedValue({ globalPause: false, enginePaused: false });
+  (emitter as any).listTasks = vi.fn();
+  (emitter as any).updateTask = vi.fn().mockResolvedValue(undefined);
+  (emitter as any).moveTask = vi.fn().mockResolvedValue(undefined);
+  (emitter as any).logEntry = vi.fn().mockResolvedValue(undefined);
+  (emitter as any).recordRunAuditEvent = vi.fn().mockResolvedValue(undefined);
+  (emitter as any).createTask = vi.fn();
+  (emitter as any).clearStaleExecutionStartBranchReferences = vi.fn().mockReturnValue([]);
+  return emitter;
+}
+
+describe("reliability interactions: branch recovery + orphan rescue", () => {
+  let store: TaskStore & EventEmitter;
+  let manager: SelfHealingManager;
+
+  beforeEach(() => {
+    store = createStore();
+    manager = new SelfHealingManager(store, { rootDir: "/tmp/repo" });
+    vi.spyOn(worktreePool, "isUsableTaskWorktree").mockResolvedValue(true);
+  });
+
+  it("keeps userPaused tasks unswept even if reclaimable", async () => {
+    (store.listTasks as any)
+      .mockResolvedValueOnce([{ id: "FN-4429", column: "todo", checkedOutBy: null, branch: "fusion/fn-4429", worktree: "/tmp/fn-4429", paused: true, userPaused: true, pausedReason: "branch-conflict-unrecoverable" }])
+      .mockResolvedValueOnce([])
+      .mockResolvedValueOnce([]);
+
+    const inspectSpy = vi.spyOn(branchConflicts, "inspectBranchConflict");
+    const recovered = await manager.reclaimSelfOwnedBranchConflicts();
+
+    expect(recovered).toBe(0);
+    expect(inspectSpy).not.toHaveBeenCalled();
+  });
+
+  it("orphan-rescue sweep is idempotent across consecutive runs", async () => {
+    const branch = "fusion/fn-4470";
+    vi.spyOn(worktreePool, "scanOrphanedBranches")
+      .mockResolvedValueOnce([branch])
+      .mockResolvedValueOnce([branch]);
+    vi.spyOn(manager as any, "inspectOrphanedBranch")
+      .mockResolvedValueOnce({ branch, tipSha: "abc123", uniqueCommitCount: 2, uniqueCommitSubjects: ["feat: keep work"], derivedTaskId: "FN-4470", registeredWorktreePath: null })
+      .mockResolvedValueOnce({ branch, tipSha: "abc123", uniqueCommitCount: 2, uniqueCommitSubjects: ["feat: keep work"], derivedTaskId: "FN-4470", registeredWorktreePath: null });
+
+    (store.listTasks as any)
+      .mockResolvedValueOnce([])
+      .mockResolvedValueOnce([{ id: "FN-5001", column: "triage", branch }]);
+    (store.createTask as any).mockResolvedValueOnce({ id: "FN-5001", lineageId: "lin-5001" });
+
+    await manager.cleanupOrphanedBranches();
+    await manager.cleanupOrphanedBranches();
+
+    expect(store.createTask).toHaveBeenCalledTimes(1);
+  });
+});