feat(server): 添加 session 持久化支持

- 复用 core 包的 SessionStorage 实现文件持久化
- sessions 保存到 ~/.local/share/ai-assist/sessions/
- 服务启动时自动加载已持久化的 sessions
- create/addMessage/delete 操作自动同步到文件

packages/server/src/agent/adapter.ts

@@ -148,7 +148,7 @@ export async function processMessage(sessionId: string, content: string): Promis
       },
     });
 
-    const assistantMessage = sessionManager.addMessage(sessionId, {
+    const assistantMessage = await sessionManager.addMessage(sessionId, {
       role: 'assistant',
       content: 'Agent core module not available. Please build @ai-assistant/core first.',
     });
@@ -184,7 +184,7 @@ export async function processMessage(sessionId: string, content: string): Promis
     });
 
     // 保存助手消息
-    const assistantMessage = sessionManager.addMessage(sessionId, {
+    const assistantMessage = await sessionManager.addMessage(sessionId, {
       role: 'assistant',
       content: response,
     });

packages/server/src/index.ts

@@ -165,6 +165,10 @@ export function createServer(options: ServerOptions = {}) {
  * 初始化服务器（加载 core 模块等）
  */
 export async function initServer(options: ServerOptions = {}): Promise<void> {
+  // 初始化 SessionManager（加载持久化的 sessions）
+  const sessionManager = getSessionManager();
+  await sessionManager.init();
+
   // 尝试加载 core 模块
   const coreLoaded = await initCore();
   if (coreLoaded) {

packages/server/src/routes/sessions.ts

@@ -30,7 +30,7 @@ sessionsRouter.post('/', async (c) => {
   try {
     const body = await c.req.json();
     const input = CreateSessionInputSchema.parse(body);
-    const session = sessionManager.create(input);
+    const session = await sessionManager.create(input);
 
     return c.json(
       {
@@ -76,7 +76,7 @@ sessionsRouter.get('/:id', (c) => {
 /**
  * DELETE /sessions/:id - 删除会话
  */
-sessionsRouter.delete('/:id', (c) => {
+sessionsRouter.delete('/:id', async (c) => {
   const id = c.req.param('id');
 
   if (!sessionManager.exists(id)) {
@@ -89,7 +89,7 @@ sessionsRouter.delete('/:id', (c) => {
     );
   }
 
-  sessionManager.delete(id);
+  await sessionManager.delete(id);
 
   return c.json({
     success: true,
@@ -144,7 +144,7 @@ sessionsRouter.post('/:id/messages', async (c) => {
     const body = await c.req.json();
     const input = SendMessageInputSchema.parse(body);
 
-    const message = sessionManager.addMessage(id, {
+    const message = await sessionManager.addMessage(id, {
       role: input.role,
       content: input.content,
     });

packages/server/src/session/manager.ts

@@ -1,23 +1,160 @@
 /**
  * Session Manager
  *
- * 管理所有活跃的会话
+ * 管理所有活跃的会话，支持文件持久化
  */
 
 import { v4 as uuidv4 } from 'uuid';
 import type { Session, CreateSessionInput, Message, SessionStatus } from '../types.js';
 
+// ============================================================================
+// Core 模块接口定义（避免构建时依赖）
+// ============================================================================
+
+interface SessionData {
+  id: string;
+  parentId?: string;
+  agentName?: string;
+  createdAt: string;
+  updatedAt: string;
+  workdir: string;
+  title?: string;
+  messages: Array<{ role: string; content: unknown }>;
+  discoveredTools: string[];
+  todos: unknown[];
+}
+
+interface SessionStorageInterface {
+  ensureDir(): Promise<void>;
+  generateSessionId(): string;
+  listSessions(): Promise<Array<{ id: string; title: string; workdir: string; messageCount: number; createdAt: string; updatedAt: string }>>;
+  loadSession(sessionId: string): Promise<SessionData | null>;
+  saveSession(session: SessionData): Promise<void>;
+  deleteSession(sessionId: string): Promise<boolean>;
+}
+
+// ============================================================================
+// 消息格式转换
+// ============================================================================
+
+/**
+ * 将 Server Message 转换为 Core ModelMessage 格式
+ */
+function toModelMessage(msg: Message): { role: string; content: string } {
+  return { role: msg.role, content: msg.content };
+}
+
+/**
+ * 将 Core ModelMessage 转换为 Server Message 格式
+ */
+function fromModelMessage(
+  msg: { role: string; content: unknown },
+  sessionId: string,
+  index: number
+): Message {
+  return {
+    id: uuidv4(),
+    sessionId,
+    role: msg.role as 'user' | 'assistant' | 'system' | 'tool',
+    content: typeof msg.content === 'string' ? msg.content : JSON.stringify(msg.content),
+    createdAt: new Date().toISOString(),
+  };
+}
+
+// ============================================================================
+// SessionManager 类
+// ============================================================================
+
 export class SessionManager {
   private sessions: Map<string, Session> = new Map();
   private messages: Map<string, Message[]> = new Map();
+  private storage: SessionStorageInterface | null = null;
+  private initialized = false;
+
+  /**
+   * 初始化：加载 Core 模块的 SessionStorage 并恢复已有 sessions
+   */
+  async init(): Promise<void> {
+    if (this.initialized) return;
+
+    try {
+      // 动态导入 Core 模块，避免构建时依赖
+      const corePath = '@ai-assistant/core';
+      const core = await import(/* webpackIgnore: true */ corePath) as {
+        SessionStorage: new () => SessionStorageInterface;
+      };
+
+      this.storage = new core.SessionStorage();
+      await this.storage.ensureDir();
+
+      // 加载已持久化的 sessions
+      const summaries = await this.storage.listSessions();
+      console.log(`[SessionManager] Found ${summaries.length} persisted sessions`);
+
+      for (const summary of summaries) {
+        const sessionData = await this.storage.loadSession(summary.id);
+        if (!sessionData) continue;
+
+        // 转换为 Server Session 格式
+        const session: Session = {
+          id: sessionData.id,
+          name: sessionData.title,
+          workdir: sessionData.workdir,
+          createdAt: sessionData.createdAt,
+          updatedAt: sessionData.updatedAt,
+          status: 'idle',
+          messageCount: sessionData.messages.length,
+        };
+
+        this.sessions.set(session.id, session);
+
+        // 转换消息格式
+        const messages = sessionData.messages.map((msg, i) =>
+          fromModelMessage(msg, session.id, i)
+        );
+        this.messages.set(session.id, messages);
+      }
+
+      console.log(`[SessionManager] Loaded ${this.sessions.size} sessions from storage`);
+    } catch (error) {
+      console.warn('[SessionManager] Storage not available, using memory only:', error);
+    }
+
+    this.initialized = true;
+  }
+
+  /**
+   * 持久化单个 session
+   */
+  private async persist(sessionId: string): Promise<void> {
+    if (!this.storage) return;
+
+    const session = this.sessions.get(sessionId);
+    const messages = this.messages.get(sessionId) || [];
+
+    if (!session) return;
+
+    const sessionData: SessionData = {
+      id: session.id,
+      createdAt: session.createdAt,
+      updatedAt: session.updatedAt,
+      workdir: session.workdir,
+      title: session.name,
+      messages: messages.map(toModelMessage),
+      discoveredTools: [],
+      todos: [],
+    };
+
+    await this.storage.saveSession(sessionData);
+  }
 
   /**
    * 创建新会话
    */
-  create(input: CreateSessionInput = {}): Session {
+  async create(input: CreateSessionInput = {}): Promise<Session> {
     const now = new Date().toISOString();
     const session: Session = {
-      id: uuidv4(),
+      id: this.storage?.generateSessionId() || uuidv4(),
       name: input.name,
       workdir: input.workdir || process.cwd(),
       createdAt: now,
@@ -29,6 +166,9 @@ export class SessionManager {
     this.sessions.set(session.id, session);
     this.messages.set(session.id, []);
 
+    // 持久化
+    await this.persist(session.id);
+
     return session;
   }
 
@@ -51,9 +191,16 @@ export class SessionManager {
   /**
    * 删除会话
    */
-  delete(id: string): boolean {
+  async delete(id: string): Promise<boolean> {
     this.messages.delete(id);
-    return this.sessions.delete(id);
+    const deleted = this.sessions.delete(id);
+
+    // 从存储中删除
+    if (deleted && this.storage) {
+      await this.storage.deleteSession(id);
+    }
+
+    return deleted;
   }
 
   /**
@@ -78,7 +225,10 @@ export class SessionManager {
   /**
    * 添加消息
    */
-  addMessage(sessionId: string, message: Omit<Message, 'id' | 'sessionId' | 'createdAt'>): Message | undefined {
+  async addMessage(
+    sessionId: string,
+    message: Omit<Message, 'id' | 'sessionId' | 'createdAt'>
+  ): Promise<Message | undefined> {
     const session = this.sessions.get(sessionId);
     if (!session) return undefined;
 
@@ -97,6 +247,9 @@ export class SessionManager {
     session.messageCount = messages.length;
     session.updatedAt = new Date().toISOString();
 
+    // 持久化
+    await this.persist(sessionId);
+
     return fullMessage;
   }