feat: add stable scheduled tasks

Scheduled tasks previously created separate visible work for each run and lacked one conversation-backed product identity. Custom tasks now create or reuse one stable Task and Conversation, reuse that identity across triggers, and write text results back with Task provenance.

Tasks default to Execute while preserving the configured Runtime, tool authorization, and high-risk approval boundaries. Schema v22 backfills existing schedules to stable Task and Conversation links without deleting historical runs.

The conversation list, conversation Task strip, and Task Center now expose the same Task, with localized status metadata, overflow-aware titles, and shared schedule controls.

Release note: 现在可以创建关联当前或新会话的定制计划任务；重复执行会复用同一 Task 并将文本结果回写会话，左侧会话列表和 Task Center 可直接查看和管理。

src/main/ipc.test.ts

@@ -2668,7 +2668,14 @@ describe('registerIpcHandlers agent terminal state', () => {
         updatedAt: Date.now(),
         messages: []
       })),
+      appendConversationMessage: vi.fn(),
       appendRemoteConversationMessage: vi.fn(),
+      completeScheduleRun: vi.fn(),
+      claimScheduleNow: vi.fn(),
+      listSchedules: vi.fn(() => []),
+      createSchedule: vi.fn(),
+      setScheduleEnabled: vi.fn(),
+      removeSchedule: vi.fn(),
       upsertModelUsageCall: vi.fn(),
       clearAssistantData: vi.fn(),
       listExperts: vi.fn<() => Array<Record<string, unknown>>>(() => []),
@@ -2799,6 +2806,140 @@ describe('registerIpcHandlers agent terminal state', () => {
     senderFrame: webContents.mainFrame
   })
 
+  it('defaults custom scheduled Tasks to Execute', async () => {
+    const harness = createHarness({
+      runtimeId: 'continue',
+      capability: 'chat',
+      supportsToolExecution: true,
+      async *run() {
+        yield { type: 'done', requestId: 'unused' } as const
+      }
+    })
+    const conversationId =
+      '00000000-0000-4000-8000-000000000705'
+    const createInput = {
+      projectId: '00000000-0000-4000-8000-000000000401',
+      conversationId,
+      title: '每周汇总',
+      prompt: '汇总本周进展',
+      recurrence: 'weekly' as const,
+      nextRunAt: '2026-08-21T09:00:00.000Z'
+    }
+
+    await electronMocks.handlers.get(
+      ipcChannels.schedulesCreate
+    )?.(trustedEvent(harness.webContents), createInput)
+
+    expect(
+      harness.assistantDatabase.createSchedule
+    ).toHaveBeenCalledWith({
+      ...createInput,
+      workMode: 'execute'
+    })
+    await harness.dispose()
+  })
+
+  it('reuses a scheduled Task and writes text results to its Conversation', async () => {
+    const taskId = '00000000-0000-4000-8000-000000000701'
+    const conversationId =
+      '00000000-0000-4000-8000-000000000702'
+    const scheduleId =
+      '00000000-0000-4000-8000-000000000703'
+    const runId = '00000000-0000-4000-8000-000000000704'
+    const runtime = {
+      runtimeId: 'model',
+      capability: 'chat',
+      supportsToolExecution: true,
+      async *run(
+        request: { requestId: string },
+        _signal: AbortSignal,
+        authorize: (
+          input: {
+            scopeKey: string
+            title: string
+            description: string
+          }
+        ) => Promise<string>
+      ) {
+        expect(request.requestId).toBe(runId)
+        await authorize({
+          scopeKey: 'workspace.write',
+          title: '写入工作区',
+          description: '更新状态文件'
+        })
+        yield {
+          requestId: request.requestId,
+          type: 'text',
+          delta: '每日状态正常'
+        } as const
+        yield {
+          requestId: request.requestId,
+          type: 'done'
+        } as const
+      }
+    }
+    const harness = createHarness(runtime)
+    const schedule = {
+      id: scheduleId,
+      projectId: '00000000-0000-4000-8000-000000000401',
+      taskId,
+      conversationId,
+      title: '每日状态',
+      prompt: '汇总状态',
+      workMode: 'execute' as const,
+      recurrence: 'daily' as const,
+      nextRunAt: '2026-08-20T00:00:00.000Z',
+      enabled: true,
+      createdAt: '2026-08-19T00:00:00.000Z',
+      updatedAt: '2026-08-19T00:00:00.000Z'
+    }
+    harness.assistantDatabase.claimScheduleNow.mockReturnValue({
+      schedule,
+      runId
+    })
+    harness.approvalBroker.request.mockResolvedValue('once')
+
+    await electronMocks.handlers.get(
+      ipcChannels.schedulesRunNow
+    )?.(trustedEvent(harness.webContents), scheduleId)
+
+    await vi.waitFor(() =>
+      expect(
+        harness.assistantDatabase.completeScheduleRun
+      ).toHaveBeenCalledWith(runId, 'completed')
+    )
+    expect(
+      harness.assistantDatabase.updateTaskStatus
+    ).toHaveBeenCalledWith(taskId, 'running')
+    expect(harness.approvalBroker.request).toHaveBeenCalledWith(
+      expect.objectContaining({
+        requestId: taskId,
+        conversationId
+      }),
+      expect.any(AbortSignal),
+      expect.any(Function)
+    )
+    expect(
+      harness.assistantDatabase.appendConversationMessage
+    ).toHaveBeenCalledWith({
+      conversationId,
+      role: 'assistant',
+      content: '每日状态正常',
+      status: '定时任务',
+      task: {
+        id: taskId,
+        title: '每日状态'
+      }
+    })
+    expect(
+      harness.assistantDatabase.createTextArtifact
+    ).not.toHaveBeenCalled()
+    expect(harness.webContents.send).toHaveBeenCalledWith(
+      ipcChannels.conversationsChanged
+    )
+    await harness.dispose()
+  })
+
   it('publishes Runtime usage as context metrics with one settings read', async () => {
     const runtime = {
       runtimeId: 'continue',