refactor(core): 拆分大型单体文件为模块化子组件

将三个超过 700 行的大型文件重构为模块化架构:

Agent (1033 → ~400 行):
- agent-tool-executor: 工具获取、过滤和执行
- agent-message-handler: 消息构建、流式处理
- agent-mode-manager: 模式切换和权限检查
- agent-vision-handler: 视觉处理委托

CheckpointManager (1015 → ~620 行):
- checkpoint-store: 检查点 CRUD 操作
- checkpoint-rollback: 回滚和撤销操作
- checkpoint-session: 会话跟踪
- checkpoint-events: 事件发射系统

SessionManager (768 → 356 行):
- message-converter: Part ↔ ModelMessage 转换
- session-store: 会话 CRUD 操作
- project-manager: 项目管理
- session-auto-save: 自动保存功能

重构原则: 单一职责、编排器模式、向后兼容 API

packages/core/src/session/manager.ts

@@ -1,48 +1,19 @@
+/**
+ * 会话管理器
+ * 作为编排器，委托具体工作给各个子模块
+ */
+
 import type { ModelMessage } from 'ai';
 import * as storage from './storage/index.js';
-import { SessionStorage, MessageStorage, PartStorage, TodoStorage } from './storage/index.js';
-import type { SessionInfo, Part, TodoItem } from './storage/index.js';
-import { generateSessionId } from './id.js';
-import { getProjectId, isGitRepository } from './project.js';
+import type { TodoItem } from './storage/index.js';
 
-/**
- * 会话摘要（用于列表展示）
- */
-export interface SessionSummary {
-  id: string;
-  title: string;
-  workdir: string;
-  messageCount: number;
-  createdAt: string;
-  updatedAt: string;
-}
+// 子模块
+import { SessionStore, type SessionData, type SessionSummary } from './session-store.js';
+import { ProjectManager, type ProjectMetadata } from './project-manager.js';
+import { SessionAutoSave } from './session-auto-save.js';
 
-/**
- * 运行时会话数据（兼容旧接口）
- */
-export interface SessionData {
-  id: string;
-  projectId: string;
-  parentId?: string;
-  agentName?: string;
-  createdAt: string;
-  updatedAt: string;
-  workdir: string;
-  title?: string;
-  messages: ModelMessage[];
-  discoveredTools: string[];
-  todos: TodoItem[];
-}
-
-/**
- * 项目元数据
- */
-export interface ProjectMetadata {
-  id: string;
-  workdir: string;
-  createdAt: string;
-  isGitRepo: boolean;
-}
+// 重新导出类型
+export type { SessionData, SessionSummary, ProjectMetadata };
 
 /**
  * 会话管理器
@@ -50,14 +21,24 @@ export interface ProjectMetadata {
  */
 export class SessionManager {
   private currentSession: SessionData | null = null;
-  private currentProject: ProjectMetadata | null = null;
-  private autoSaveInterval: ReturnType<typeof setInterval> | null = null;
   private storageDir?: string;
 
+  // 子模块
+  private store: SessionStore;
+  private projectManager: ProjectManager;
+  private autoSave: SessionAutoSave;
+
   constructor(storageDir?: string) {
     this.storageDir = storageDir;
+    this.store = new SessionStore();
+    this.projectManager = new ProjectManager();
+    this.autoSave = new SessionAutoSave();
   }
 
+  // ============================================================================
+  // 初始化
+  // ============================================================================
+
   /**
    * 初始化 - 尝试恢复或创建新会话
    */
@@ -66,13 +47,14 @@ export class SessionManager {
     await storage.initStorage(this.storageDir);
 
     // 获取或创建项目
-    this.currentProject = await this.getOrCreateProject(workdir);
+    await this.projectManager.getOrCreate(workdir);
 
     // 尝试加载当前会话
     const currentSessionId = await this.getCurrentSessionId();
 
     if (currentSessionId) {
-      const existing = await this.loadSession(this.currentProject.id, currentSessionId);
+      const projectId = this.projectManager.getProjectId()!;
+      const existing = await this.store.load(projectId, currentSessionId);
 
       if (existing && existing.workdir === workdir) {
         this.currentSession = existing;
@@ -82,218 +64,18 @@ export class SessionManager {
     }
 
     // 创建新会话
-    this.currentSession = await this.createNewSession(workdir);
-    await this.saveSessionInfo();
+    const projectId = this.projectManager.getProjectId()!;
+    this.currentSession = await this.store.create(projectId, workdir);
+    await this.store.save(this.currentSession);
     await this.setCurrentSessionPointer(this.currentSession.id);
 
     this.startAutoSave();
     return this.currentSession;
   }
 
-  /**
-   * 获取或创建项目
-   */
-  private async getOrCreateProject(workdir: string): Promise<ProjectMetadata> {
-    const projectId = await getProjectId(workdir);
-
-    try {
-      const existing = await storage.read<ProjectMetadata>(['project', projectId]);
-      return existing;
-    } catch (e) {
-      if (e instanceof storage.StorageNotFoundError) {
-        const isGitRepo = await isGitRepository(workdir);
-        const project: ProjectMetadata = {
-          id: projectId,
-          workdir,
-          createdAt: new Date().toISOString(),
-          isGitRepo,
-        };
-        await storage.write(['project', projectId], project);
-        return project;
-      }
-      throw e;
-    }
-  }
-
-  /**
-   * 创建新会话
-   */
-  private async createNewSession(workdir: string): Promise<SessionData> {
-    if (!this.currentProject) {
-      throw new Error('Project not initialized. Call init() first.');
-    }
-
-    const sessionInfo = await SessionStorage.create(this.currentProject.id, workdir);
-
-    return {
-      id: sessionInfo.id,
-      projectId: sessionInfo.projectId,
-      createdAt: new Date(sessionInfo.createdAt).toISOString(),
-      updatedAt: new Date(sessionInfo.updatedAt).toISOString(),
-      workdir: sessionInfo.workdir,
-      title: sessionInfo.title,
-      messages: [],
-      discoveredTools: sessionInfo.discoveredTools,
-      todos: [],
-    };
-  }
-
-  /**
-   * 加载会话（从存储重建）
-   */
-  private async loadSession(projectId: string, sessionId: string): Promise<SessionData | null> {
-    const sessionInfo = await SessionStorage.get(projectId, sessionId);
-    if (!sessionInfo) return null;
-
-    // 加载消息
-    const messages = await this.loadMessagesFromStorage(sessionId);
-
-    // 加载 todos
-    const todoList = await TodoStorage.get(sessionId);
-
-    return {
-      id: sessionInfo.id,
-      projectId: sessionInfo.projectId,
-      parentId: sessionInfo.parentId,
-      agentName: sessionInfo.agentName,
-      createdAt: new Date(sessionInfo.createdAt).toISOString(),
-      updatedAt: new Date(sessionInfo.updatedAt).toISOString(),
-      workdir: sessionInfo.workdir,
-      title: sessionInfo.title,
-      messages,
-      discoveredTools: sessionInfo.discoveredTools,
-      todos: todoList?.items || [],
-    };
-  }
-
-  /**
-   * 从存储加载消息并转换为 AI SDK 格式
-   */
-  private async loadMessagesFromStorage(sessionId: string): Promise<ModelMessage[]> {
-    const messageInfos = await MessageStorage.listBySession(sessionId);
-    const messages: ModelMessage[] = [];
-
-    for (const messageInfo of messageInfos) {
-      const parts = await PartStorage.getByIds(messageInfo.id, messageInfo.partIds);
-      const modelMessages = this.partsToModelMessages(messageInfo.role, parts);
-      messages.push(...modelMessages);
-    }
-
-    return messages;
-  }
-
-  /**
-   * 将 Parts 转换为 AI SDK ModelMessage（用于加载历史消息）
-   *
-   * 新逻辑：
-   * - user 消息：直接转换
-   * - assistant 消息：转换文本和工具调用，然后为已完成的工具生成 tool 消息
-   */
-  private partsToModelMessages(role: string, parts: Part[]): ModelMessage[] {
-    if (parts.length === 0) return [];
-
-    const result: ModelMessage[] = [];
-
-    if (role === 'user') {
-      // User 消息：只有文本和文件
-      const content: unknown[] = [];
-      for (const part of parts) {
-        if (part.type === 'text') {
-          content.push({ type: 'text', text: part.text });
-        } else if (part.type === 'file') {
-          content.push({
-            type: 'image',
-            image: part.data,
-            mimeType: part.mimeType,
-          });
-        }
-      }
-
-      if (content.length === 1 && (content[0] as { type: string }).type === 'text') {
-        result.push({
-          role: 'user',
-          content: (content[0] as { text: string }).text,
-        });
-      } else if (content.length > 0) {
-        result.push({
-          role: 'user',
-          content,
-        } as ModelMessage);
-      }
-
-    } else if (role === 'assistant') {
-      // Assistant 消息：文本 + 工具调用
-      const content: unknown[] = [];
-      // input 使用 unknown 类型以兼容 AI SDK（可能是对象、字符串等）
-      const completedTools: Array<{ toolCallId: string; toolName: string; input: unknown; output: unknown }> = [];
-
-      for (const part of parts) {
-        if (part.type === 'text') {
-          content.push({ type: 'text', text: part.text });
-        } else if (part.type === 'tool') {
-          // 只有非 pending 状态的工具调用才添加到 AI SDK 消息
-          if (part.state.status !== 'pending') {
-            // AI SDK v5 使用 input 字段（不是 args）
-            content.push({
-              type: 'tool-call',
-              toolCallId: part.toolCallId,
-              toolName: part.toolName,
-              input: part.state.input,
-            });
-
-            // 收集已完成的工具结果
-            if (part.state.status === 'completed') {
-              completedTools.push({
-                toolCallId: part.toolCallId,
-                toolName: part.toolName,
-                input: part.state.input,
-                output: part.state.output,
-              });
-            } else if (part.state.status === 'error') {
-              completedTools.push({
-                toolCallId: part.toolCallId,
-                toolName: part.toolName,
-                input: part.state.input,
-                output: part.state.error,
-              });
-            }
-          }
-        } else if (part.type === 'reasoning') {
-          content.push({ type: 'text', text: `[Reasoning] ${part.text}` });
-        }
-      }
-
-      // 添加 assistant 消息
-      if (content.length === 1 && (content[0] as { type: string }).type === 'text') {
-        result.push({
-          role: 'assistant',
-          content: (content[0] as { text: string }).text,
-        });
-      } else if (content.length > 0) {
-        result.push({
-          role: 'assistant',
-          content,
-        } as ModelMessage);
-      }
-
-      // 添加 tool 消息（如果有已完成的工具）
-      // AI SDK v5 要求 tool-result 必须包含 input 和 output 字段
-      if (completedTools.length > 0) {
-        result.push({
-          role: 'tool',
-          content: completedTools.map((t) => ({
-            type: 'tool-result',
-            toolCallId: t.toolCallId,
-            toolName: t.toolName,
-            input: t.input,
-            output: t.output,
-          })),
-        } as unknown as ModelMessage);
-      }
-    }
-
-    return result;
-  }
+  // ============================================================================
+  // 会话获取
+  // ============================================================================
 
   /**
    * 获取当前会话
@@ -306,189 +88,108 @@ export class SessionManager {
    * 获取当前项目
    */
   getProject(): ProjectMetadata | null {
-    return this.currentProject;
+    return this.projectManager.getProject();
   }
 
   /**
-   * 保存会话信息
+   * 获取当前会话 ID
    */
-  private async saveSessionInfo(): Promise<void> {
-    if (!this.currentSession) return;
-
-    const sessionInfo: SessionInfo = {
-      id: this.currentSession.id,
-      projectId: this.currentSession.projectId,
-      parentId: this.currentSession.parentId,
-      agentName: this.currentSession.agentName,
-      createdAt: new Date(this.currentSession.createdAt).getTime(),
-      updatedAt: Date.now(),
-      workdir: this.currentSession.workdir,
-      title: this.currentSession.title,
-      discoveredTools: this.currentSession.discoveredTools,
-      stats: {
-        messageCount: this.currentSession.messages.length,
-        inputTokens: 0,
-        outputTokens: 0,
-      },
-    };
-
-    await SessionStorage.save(sessionInfo);
+  getSessionId(): string | undefined {
+    return this.currentSession?.id;
   }
 
+  // ============================================================================
+  // 会话操作
+  // ============================================================================
+
   /**
    * 保存当前会话
    */
   async save(): Promise<void> {
     if (!this.currentSession) return;
-    await this.saveSessionInfo();
+    await this.store.save(this.currentSession);
   }
 
   /**
-   * 同步消息到存储（将 AI SDK 消息转换为 Message + Parts）
-   *
-   * 新逻辑：只存储 user 和 assistant 消息
-   * - user 消息：直接存储
-   * - assistant 消息：合并后续的 tool 消息中的工具结果
-   * - tool 消息：跳过（结果合并到 assistant）
+   * 清空当前会话并创建新会话
    */
-  async syncMessages(messages: ModelMessage[]): Promise<void> {
-    if (!this.currentSession) return;
-
-    const sessionId = this.currentSession.id;
-
-    // 删除旧消息
-    await MessageStorage.removeBySession(sessionId);
-
-    // 用于跟踪当前 assistant 消息的工具调用
-    let currentAssistantMsgId: string | null = null;
-    let currentUserMsgId: string | null = null;
-    const toolCallPartIds = new Map<string, string>(); // toolCallId -> partId
-
-    for (let i = 0; i < messages.length; i++) {
-      const message = messages[i];
-
-      if (message.role === 'user') {
-        // User 消息
-        const messageInfo = await MessageStorage.create(sessionId, 'user');
-        currentUserMsgId = messageInfo.id;
-        const partIds: string[] = [];
-
-        if (typeof message.content === 'string') {
-          const part = await PartStorage.createText(messageInfo.id, message.content);
-          partIds.push(part.id);
-        } else if (Array.isArray(message.content)) {
-          for (const item of message.content) {
-            const itemType = (item as { type: string }).type;
-            if (itemType === 'text') {
-              const part = await PartStorage.createText(messageInfo.id, (item as { text: string }).text);
-              partIds.push(part.id);
-            } else if (itemType === 'image') {
-              const img = item as unknown as { image: string; mimeType: string };
-              const part = await PartStorage.create(messageInfo.id, 'file', {
-                filename: 'image',
-                mimeType: img.mimeType,
-                data: typeof img.image === 'string' ? img.image : '',
-              });
-              partIds.push(part.id);
-            }
-          }
-        }
-
-        if (partIds.length > 0) {
-          await MessageStorage.update(sessionId, messageInfo.id, { partIds });
-        }
-
-        // 重置工具调用追踪
-        currentAssistantMsgId = null;
-        toolCallPartIds.clear();
-
-      } else if (message.role === 'assistant') {
-        // Assistant 消息：如果当前轮次已有 assistant 消息，则追加 Parts
-        let messageId: string;
-        let existingPartIds: string[] = [];
-
-        if (currentAssistantMsgId) {
-          // 同一轮对话的后续 assistant 消息，追加到现有消息
-          messageId = currentAssistantMsgId;
-          const existingMsg = await MessageStorage.get(sessionId, messageId);
-          existingPartIds = existingMsg?.partIds ?? [];
-        } else {
-          // 新的 assistant 消息
-          const messageInfo = await MessageStorage.create(sessionId, 'assistant', {
-            parentId: currentUserMsgId ?? undefined,
-          });
-          messageId = messageInfo.id;
-          currentAssistantMsgId = messageId;
-        }
-
-        const newPartIds: string[] = [];
-
-        if (typeof message.content === 'string') {
-          const part = await PartStorage.createText(messageId, message.content);
-          newPartIds.push(part.id);
-        } else if (Array.isArray(message.content)) {
-          for (const item of message.content) {
-            const itemType = (item as { type: string }).type;
-            if (itemType === 'text') {
-              const part = await PartStorage.createText(messageId, (item as { text: string }).text);
-              newPartIds.push(part.id);
-            } else if (itemType === 'tool-call') {
-              // AI SDK 的 tool-call 使用 input 字段存储参数（不是 args）
-              const toolCall = item as unknown as { toolCallId: string; toolName: string; input: Record<string, unknown> };
-              // 创建 running 状态的工具 Part
-              const part = await PartStorage.createToolRunning(
-                messageId,
-                toolCall.toolCallId,
-                toolCall.toolName,
-                (toolCall.input as Record<string, unknown>) ?? {}
-              );
-              newPartIds.push(part.id);
-              toolCallPartIds.set(toolCall.toolCallId, part.id);
-            }
-          }
-        }
-
-        if (newPartIds.length > 0) {
-          // 合并已有的和新的 partIds
-          const allPartIds = [...existingPartIds, ...newPartIds];
-          await MessageStorage.update(sessionId, messageId, { partIds: allPartIds });
-        }
-
-      } else if (message.role === 'tool' && currentAssistantMsgId) {
-        // Tool 消息：更新对应 assistant 消息中的工具 Part 状态
-        if (Array.isArray(message.content)) {
-          for (const item of message.content) {
-            const itemType = (item as { type: string }).type;
-            if (itemType === 'tool-result') {
-              // AI SDK v5 使用 output 字段存储结果（不是 result）
-              const toolResult = item as unknown as { toolCallId: string; toolName: string; output: unknown };
-              const partId = toolCallPartIds.get(toolResult.toolCallId);
-              if (partId) {
-                // 更新工具状态为 completed
-                // 获取原始 start time
-                const part = await PartStorage.get(currentAssistantMsgId, partId);
-                const startTime = part?.type === 'tool' && part.state.status === 'running'
-                  ? part.state.time.start
-                  : Date.now();
-                await PartStorage.setToolCompleted(currentAssistantMsgId, partId, toolResult.output, startTime);
-              }
-            }
-          }
-        }
-        // 不创建新消息，跳过 tool role
-      }
-      // 忽略 system 消息（system prompt 通过其他方式注入）
+  async newSession(workdir?: string): Promise<SessionData> {
+    if (!this.projectManager.isInitialized()) {
+      throw new Error('Project not initialized. Call init() first.');
     }
+
+    const newWorkdir = workdir || this.currentSession?.workdir || process.cwd();
+
+    // 如果工作目录变化，需要切换项目
+    if (workdir && workdir !== this.projectManager.getProject()?.workdir) {
+      await this.projectManager.switchProject(workdir);
+    }
+
+    const projectId = this.projectManager.getProjectId()!;
+    this.currentSession = await this.store.create(projectId, newWorkdir);
+    await this.store.save(this.currentSession);
+    await this.setCurrentSessionPointer(this.currentSession.id);
+
+    return this.currentSession;
   }
 
+  /**
+   * 恢复指定会话
+   */
+  async restoreSession(sessionId: string): Promise<SessionData | null> {
+    if (!this.projectManager.isInitialized()) {
+      throw new Error('Project not initialized. Call init() first.');
+    }
+
+    const projectId = this.projectManager.getProjectId()!;
+    const session = await this.store.load(projectId, sessionId);
+    if (!session) return null;
+
+    this.currentSession = session;
+    await this.setCurrentSessionPointer(sessionId);
+
+    return session;
+  }
+
+  /**
+   * 列出当前项目的历史会话
+   */
+  async listSessions(): Promise<SessionSummary[]> {
+    const projectId = this.projectManager.getProjectId();
+    if (!projectId) {
+      return this.listAllSessions();
+    }
+    return this.store.listByProject(projectId);
+  }
+
+  /**
+   * 列出所有项目的会话
+   */
+  async listAllSessions(): Promise<SessionSummary[]> {
+    return this.store.listAll();
+  }
+
+  /**
+   * 删除历史会话
+   */
+  async deleteSession(sessionId: string): Promise<boolean> {
+    const projectId = this.projectManager.getProjectId();
+    if (!projectId) return false;
+    return this.store.delete(projectId, sessionId);
+  }
+
+  // ============================================================================
+  // 消息操作
+  // ============================================================================
+
   /**
    * 批量设置消息（用于同步整个对话历史）
    */
   async setMessages(messages: ModelMessage[]): Promise<void> {
     if (!this.currentSession) return;
     this.currentSession.messages = messages;
-    await this.syncMessages(messages);
-    await this.saveSessionInfo();
+    await this.store.syncMessages(this.currentSession.id, messages);
+    await this.store.save(this.currentSession);
   }
 
   /**
@@ -507,13 +208,17 @@ export class SessionManager {
     return this.currentSession?.messages || [];
   }
 
+  // ============================================================================
+  // 工具和待办操作
+  // ============================================================================
+
   /**
    * 设置已发现的工具
    */
   async setDiscoveredTools(tools: string[]): Promise<void> {
     if (!this.currentSession) return;
     this.currentSession.discoveredTools = tools;
-    await this.saveSessionInfo();
+    await this.store.save(this.currentSession);
   }
 
   /**
@@ -526,10 +231,12 @@ export class SessionManager {
   /**
    * 更新待办事项
    */
-  async setTodos(todos: Array<{ content: string; status: 'pending' | 'in_progress' | 'completed' }>): Promise<void> {
+  async setTodos(
+    todos: Array<{ content: string; status: 'pending' | 'in_progress' | 'completed' }>
+  ): Promise<void> {
     if (!this.currentSession) return;
-    const todoList = await TodoStorage.replace(this.currentSession.id, todos);
-    this.currentSession.todos = todoList.items;
+    const items = await this.store.setTodos(this.currentSession.id, todos);
+    this.currentSession.todos = items;
   }
 
   /**
@@ -539,192 +246,46 @@ export class SessionManager {
     return this.currentSession?.todos || [];
   }
 
-  /**
-   * 清空当前会话并创建新会话
-   */
-  async newSession(workdir?: string): Promise<SessionData> {
-    if (!this.currentProject) {
-      throw new Error('Project not initialized. Call init() first.');
-    }
-
-    const newWorkdir = workdir || this.currentSession?.workdir || process.cwd();
-
-    // 如果工作目录变化，需要切换项目
-    if (workdir && workdir !== this.currentProject.workdir) {
-      this.currentProject = await this.getOrCreateProject(workdir);
-    }
-
-    this.currentSession = await this.createNewSession(newWorkdir);
-    await this.saveSessionInfo();
-    await this.setCurrentSessionPointer(this.currentSession.id);
-
-    return this.currentSession;
-  }
+  // ============================================================================
+  // 子会话操作
+  // ============================================================================
 
   /**
    * 创建子会话（用于 Task 工具）
    */
   createChildSession(parentId: string, agentName: string, title?: string): SessionData {
-    if (!this.currentProject) {
+    if (!this.projectManager.isInitialized()) {
       throw new Error('Project not initialized. Call init() first.');
     }
 
+    const projectId = this.projectManager.getProjectId()!;
     const workdir = this.currentSession?.workdir || process.cwd();
-    return {
-      id: generateSessionId(),
-      projectId: this.currentProject.id,
-      parentId,
-      agentName,
-      createdAt: new Date().toISOString(),
-      updatedAt: new Date().toISOString(),
-      workdir,
-      title: title || `子任务 (@${agentName})`,
-      messages: [],
-      discoveredTools: [],
-      todos: [],
-    };
+    return this.store.createChildSession(projectId, parentId, agentName, workdir, title);
   }
 
   /**
    * 保存子会话
    */
   async saveChildSession(session: SessionData): Promise<void> {
-    const sessionInfo: SessionInfo = {
-      id: session.id,
-      projectId: session.projectId,
-      parentId: session.parentId,
-      agentName: session.agentName,
-      createdAt: new Date(session.createdAt).getTime(),
-      updatedAt: Date.now(),
-      workdir: session.workdir,
-      title: session.title,
-      discoveredTools: session.discoveredTools,
-    };
-    await SessionStorage.save(sessionInfo);
+    await this.store.saveChildSession(session);
   }
 
-  /**
-   * 获取当前会话 ID
-   */
-  getSessionId(): string | undefined {
-    return this.currentSession?.id;
-  }
+  // ============================================================================
+  // 自动保存
+  // ============================================================================
 
   /**
-   * 恢复指定会话
-   */
-  async restoreSession(sessionId: string): Promise<SessionData | null> {
-    if (!this.currentProject) {
-      throw new Error('Project not initialized. Call init() first.');
-    }
-
-    const session = await this.loadSession(this.currentProject.id, sessionId);
-    if (!session) return null;
-
-    this.currentSession = session;
-    await this.setCurrentSessionPointer(sessionId);
-
-    return session;
-  }
-
-  /**
-   * 列出当前项目的历史会话
-   */
-  async listSessions(): Promise<SessionSummary[]> {
-    if (!this.currentProject) {
-      return this.listAllSessions();
-    }
-
-    const sessions = await SessionStorage.listByProject(this.currentProject.id);
-    return sessions.map((s) => ({
-      id: s.id,
-      title: s.title || `会话 ${s.id}`,
-      workdir: s.workdir,
-      messageCount: s.stats?.messageCount || 0,
-      createdAt: new Date(s.createdAt).toISOString(),
-      updatedAt: new Date(s.updatedAt).toISOString(),
-    }));
-  }
-
-  /**
-   * 列出所有项目的会话
-   */
-  async listAllSessions(): Promise<SessionSummary[]> {
-    const sessions = await SessionStorage.listAll();
-    return sessions.map((s) => ({
-      id: s.id,
-      title: s.title || `会话 ${s.id}`,
-      workdir: s.workdir,
-      messageCount: s.stats?.messageCount || 0,
-      createdAt: new Date(s.createdAt).toISOString(),
-      updatedAt: new Date(s.updatedAt).toISOString(),
-    }));
-  }
-
-  /**
-   * 删除历史会话
-   */
-  async deleteSession(sessionId: string): Promise<boolean> {
-    if (!this.currentProject) return false;
-
-    try {
-      // 删除会话的消息和 Parts
-      const messageInfos = await MessageStorage.listBySession(sessionId);
-      for (const msg of messageInfos) {
-        await PartStorage.removeByMessage(msg.id);
-      }
-      await MessageStorage.removeBySession(sessionId);
-
-      // 删除 todos
-      await TodoStorage.removeBySession(sessionId);
-
-      // 删除会话信息
-      await SessionStorage.remove(this.currentProject.id, sessionId);
-
-      return true;
-    } catch {
-      return false;
-    }
-  }
-
-  /**
-   * 获取当前会话 ID（从存储）
-   */
-  private async getCurrentSessionId(): Promise<string | null> {
-    try {
-      const pointer = await storage.read<{ sessionId: string }>(['current-session']);
-      return pointer.sessionId;
-    } catch {
-      return null;
-    }
-  }
-
-  /**
-   * 设置当前会话指针
-   */
-  private async setCurrentSessionPointer(sessionId: string): Promise<void> {
-    await storage.write(['current-session'], { sessionId });
-  }
-
-  /**
-   * 启动自动保存（每 30 秒）
+   * 启动自动保存
    */
   private startAutoSave(): void {
-    if (this.autoSaveInterval) return;
-
-    this.autoSaveInterval = setInterval(async () => {
-      await this.save();
-    }, 30000);
+    this.autoSave.start(() => this.save());
   }
 
   /**
    * 停止自动保存
    */
   stopAutoSave(): void {
-    if (this.autoSaveInterval) {
-      clearInterval(this.autoSaveInterval);
-      this.autoSaveInterval = null;
-    }
+    this.autoSave.stop();
   }
 
   /**
@@ -735,6 +296,10 @@ export class SessionManager {
     await this.save();
   }
 
+  // ============================================================================
+  // 清理
+  // ============================================================================
+
   /**
    * 清理旧会话
    */
@@ -756,6 +321,29 @@ export class SessionManager {
     return deletedCount;
   }
 
+  // ============================================================================
+  // 辅助方法
+  // ============================================================================
+
+  /**
+   * 获取当前会话 ID（从存储）
+   */
+  private async getCurrentSessionId(): Promise<string | null> {
+    try {
+      const pointer = await storage.read<{ sessionId: string }>(['current-session']);
+      return pointer.sessionId;
+    } catch {
+      return null;
+    }
+  }
+
+  /**
+   * 设置当前会话指针
+   */
+  private async setCurrentSessionPointer(sessionId: string): Promise<void> {
+    await storage.write(['current-session'], { sessionId });
+  }
+
   /**
    * 获取存储目录
    */