feat(session): 实现会话保存和加载功能

- 在 AcpConnection 和 AcpSessionManager 中添加会话保存方法
- 在 QwenAgentManager 中实现通过 ACP 和直接保存会话的功能
- 在前端添加保存会话对话框和相关交互逻辑
- 新增 QwenSessionManager 用于直接操作文件系统保存和加载会话

packages/vscode-ide-companion/src/acp/acpConnection.ts

@@ -41,6 +41,7 @@ import { AcpSessionManager } from './acpSessionManager.js';
  * ✅ session/prompt - Send user message to agent
  * ✅ session/cancel - Cancel current generation
  * ✅ session/load - Load previous session
+ * ✅ session/save - Save current session
  *
  * Custom Methods (Not in standard ACP):
  * ⚠️  session/list - List available sessions (custom extension)
@@ -348,6 +349,21 @@ export class AcpConnection {
     await this.sessionManager.cancelSession(this.child);
   }
 
+  /**
+   * 保存当前会话
+   *
+   * @param tag - 保存标签
+   * @returns 保存响应
+   */
+  async saveSession(tag: string): Promise<AcpResponse> {
+    return this.sessionManager.saveSession(
+      tag,
+      this.child,
+      this.pendingRequests,
+      this.nextRequestId,
+    );
+  }
+
   /**
    * 断开连接
    */

packages/vscode-ide-companion/src/acp/acpSessionManager.ts

@@ -349,6 +349,40 @@ export class AcpSessionManager {
     console.log('[ACP] Cancel notification sent');
   }
 
+  /**
+   * 保存当前会话
+   *
+   * @param tag - 保存标签
+   * @param child - 子进程实例
+   * @param pendingRequests - 待处理请求映射表
+   * @param nextRequestId - 请求ID计数器
+   * @returns 保存响应
+   */
+  async saveSession(
+    tag: string,
+    child: ChildProcess | null,
+    pendingRequests: Map<number, PendingRequest<unknown>>,
+    nextRequestId: { value: number },
+  ): Promise<AcpResponse> {
+    if (!this.sessionId) {
+      throw new Error('No active ACP session');
+    }
+
+    console.log('[ACP] Saving session with tag:', tag);
+    const response = await this.sendRequest<AcpResponse>(
+      AGENT_METHODS.session_save,
+      {
+        sessionId: this.sessionId,
+        tag,
+      },
+      child,
+      pendingRequests,
+      nextRequestId,
+    );
+    console.log('[ACP] Session save response:', response);
+    return response;
+  }
+
   /**
    * 重置会话管理器状态
    */

packages/vscode-ide-companion/src/acp/schema.ts

@@ -18,9 +18,10 @@
  * ✅ initialize - Protocol initialization
  * ✅ authenticate - User authentication
  * ✅ session/new - Create new session
- * ❌ session/load - Load existing session (not implemented in CLI)
+ * ✅ session/load - Load existing session
  * ✅ session/prompt - Send user message to agent
  * ✅ session/cancel - Cancel current generation
+ * ✅ session/save - Save current session
  */
 export const AGENT_METHODS = {
   authenticate: 'authenticate',
@@ -29,6 +30,7 @@ export const AGENT_METHODS = {
   session_load: 'session/load',
   session_new: 'session/new',
   session_prompt: 'session/prompt',
+  session_save: 'session/save',
 } as const;
 
 /**