feat(FN-5233): add tombstone recreate guard and allow-resurrection delete f

Implements the FN-5233 tombstone system for soft-delete resurrection: a configurable `tombstoneWindowSeconds` deduplicates recreation of recently deleted tasks, with an `allowResurrection` flag that permits explicit resurrect-on-recreate, tombstone recreate guards in the store layer, and cleanup of

Fusion-Task-Id: FN-5233

packages/cli/src/__tests__/task-delete-allow-resurrection.test.ts

@@ -0,0 +1,71 @@
+import { afterEach, beforeEach, describe, expect, it } from "vitest";
+import { mkdtemp, mkdir, rm } from "node:fs/promises";
+import { join } from "node:path";
+import { tmpdir } from "node:os";
+
+import { TaskStore } from "@fusion/core";
+import kbExtension from "../extension.js";
+
+type RegisteredTool = {
+  name: string;
+  execute: (toolCallId: string, params: any, signal: AbortSignal | undefined, onUpdate: any, ctx: { cwd: string }) => Promise<any>;
+};
+
+function createMockAPI() {
+  const tools = new Map<string, RegisteredTool>();
+  return {
+    tools,
+    registerTool(tool: RegisteredTool) {
+      tools.set(tool.name, tool);
+    },
+    registerCommand() {
+      // no-op for tests
+    },
+    on() {
+      // no-op for tests
+    },
+  } as any;
+}
+
+describe("task delete allowResurrection plumbing", () => {
+  let rootDir: string;
+
+  beforeEach(async () => {
+    rootDir = await mkdtemp(join(tmpdir(), "fn-task-delete-allow-"));
+    await mkdir(join(rootDir, ".fusion"), { recursive: true });
+  });
+
+  afterEach(async () => {
+    await rm(rootDir, { recursive: true, force: true });
+  });
+
+  it("fn_task_delete forwards allowResurrection=true", async () => {
+    const store = new TaskStore(rootDir);
+    await store.init();
+    const task = await store.createTask({ title: "x", description: "y", column: "todo" });
+
+    const api = createMockAPI();
+    kbExtension(api);
+    const tool = api.tools.get("fn_task_delete") as RegisteredTool;
+    await tool.execute("call-1", { id: task.id, allowResurrection: true }, undefined, undefined, { cwd: rootDir });
+
+    const deleted = (store as any).readTaskFromDb(task.id, { includeDeleted: true }) as { allowResurrection?: boolean; deletedAt?: string };
+    expect(deleted.deletedAt).toBeTruthy();
+    expect(deleted.allowResurrection).toBe(true);
+  });
+
+  it("fn_task_delete defaults allowResurrection=false", async () => {
+    const store = new TaskStore(rootDir);
+    await store.init();
+    const task = await store.createTask({ title: "x", description: "y", column: "todo" });
+
+    const api = createMockAPI();
+    kbExtension(api);
+    const tool = api.tools.get("fn_task_delete") as RegisteredTool;
+    await tool.execute("call-2", { id: task.id }, undefined, undefined, { cwd: rootDir });
+
+    const deleted = (store as any).readTaskFromDb(task.id, { includeDeleted: true }) as { allowResurrection?: boolean; deletedAt?: string };
+    expect(deleted.deletedAt).toBeTruthy();
+    expect(deleted.allowResurrection).toBeUndefined();
+  });
+});