feat: 添加系统命令支持 (:clear)

- 新增系统命令模块 (core/system-commands)
  - 支持 :clear/:cls/:c 清空对话历史
  - 命令注册表支持别名
  - 可扩展的命令执行器

- Server 端支持
  - 新增 /api/system-commands API
  - WebSocket 处理系统命令消息
  - 会话清空 API 端点

- UI 端支持
  - 新增 SystemCommandMenu 组件
  - 输入 : 时显示命令建议菜单
  - 键盘导航和选择
  - 底部提示添加 : 快捷键

packages/server/src/agent/adapter.ts

@@ -643,3 +643,16 @@ export function submitUserInput(toolCallId: string, answer: string): boolean {
   const userInputWaiter = getUserInputWaiter();
   return userInputWaiter.submitInput(toolCallId, answer);
 }
+
+/**
+ * 清空 Agent 的对话历史（内存中）
+ *
+ * 用于系统命令 :clear
+ */
+export function clearAgentHistory(sessionId: string): void {
+  const agent = agentCache.get(sessionId);
+  if (agent) {
+    agent.clearHistory();
+    console.log(`[Agent] Cleared history for session ${sessionId}`);
+  }
+}

packages/server/src/agent/index.ts

@@ -17,6 +17,8 @@ export {
   compressContext,
   // 用户输入响应
   submitUserInput,
+  // 系统命令支持
+  clearAgentHistory,
   // 类型导出
   type TokenUsage,
   type CompressionResult,

packages/server/src/index.ts

@@ -9,7 +9,7 @@ import { cors } from 'hono/cors';
 import { logger } from 'hono/logger';
 import { createBunWebSocket } from 'hono/bun';
 
-import { sessionsRouter, toolsRouter, configRouter, filesRouter, commandsRouter, mcpRouter, hooksRouter, agentsRouter, checkpointsRouter, providersRouter, servicesRouter, contextRouter, lspRouter } from './routes/index.js';
+import { sessionsRouter, toolsRouter, configRouter, filesRouter, commandsRouter, mcpRouter, hooksRouter, agentsRouter, checkpointsRouter, providersRouter, servicesRouter, contextRouter, lspRouter, systemCommandsRouter } from './routes/index.js';
 import {
   handleWebSocket,
   handleWebSocketMessage,
@@ -90,6 +90,7 @@ api.route('/checkpoints', checkpointsRouter);
 api.route('/providers', providersRouter);
 api.route('/services', servicesRouter);
 api.route('/lsp', lspRouter);
+api.route('/system-commands', systemCommandsRouter);
 
 // 上下文压缩相关（挂载到根路径，内部路由包含 /sessions/:id/context）
 api.route('/', contextRouter);

packages/server/src/routes/index.ts

@@ -17,3 +17,4 @@ export { providersRouter } from './providers.js';
 export { servicesRouter } from './services.js';
 export { contextRouter } from './context.js';
 export { lspRouter } from './lsp.js';
+export { systemCommandsRouter } from './system-commands.js';

packages/server/src/routes/sessions.ts

@@ -104,6 +104,47 @@ sessionsRouter.delete('/:id', async (c) => {
   });
 });
 
+/**
+ * POST /sessions/:id/clear - 清空会话消息
+ *
+ * 删除会话的所有消息和相关数据，但保留会话本身
+ */
+sessionsRouter.post('/:id/clear', async (c) => {
+  const id = c.req.param('id');
+
+  if (!sessionManager.exists(id)) {
+    return c.json(
+      {
+        success: false,
+        error: 'Session not found',
+      },
+      404
+    );
+  }
+
+  try {
+    // 删除会话的所有消息
+    await MessageStorage.removeBySession(id);
+
+    // 重置会话状态
+    sessionManager.updateStatus(id, 'idle');
+
+    return c.json({
+      success: true,
+      message: 'Session messages cleared',
+    });
+  } catch (error) {
+    console.error('[Sessions] Failed to clear messages:', error);
+    return c.json(
+      {
+        success: false,
+        error: error instanceof Error ? error.message : 'Failed to clear messages',
+      },
+      500
+    );
+  }
+});
+
 /**
  * GET /sessions/:id/messages - 获取会话消息
  *

packages/server/src/routes/system-commands.ts

@@ -0,0 +1,57 @@
+/**
+ * System Commands API Routes
+ *
+ * 系统命令（: 前缀）相关的 REST API
+ */
+
+import { Hono } from 'hono';
+import { getSystemCommandRegistry } from '@ai-assistant/core';
+
+export const systemCommandsRouter = new Hono();
+
+/**
+ * GET /system-commands - 列出所有系统命令
+ */
+systemCommandsRouter.get('/', (c) => {
+  const registry = getSystemCommandRegistry();
+  const commands = registry.list();
+
+  return c.json({
+    success: true,
+    data: {
+      commands: commands.map((cmd) => ({
+        name: cmd.name,
+        description: cmd.description,
+        aliases: cmd.aliases || [],
+      })),
+    },
+  });
+});
+
+/**
+ * GET /system-commands/:name - 获取单个系统命令
+ */
+systemCommandsRouter.get('/:name', (c) => {
+  const name = c.req.param('name');
+  const registry = getSystemCommandRegistry();
+  const command = registry.get(name);
+
+  if (!command) {
+    return c.json(
+      {
+        success: false,
+        error: 'System command not found',
+      },
+      404
+    );
+  }
+
+  return c.json({
+    success: true,
+    data: {
+      name: command.name,
+      description: command.description,
+      aliases: command.aliases || [],
+    },
+  });
+});

packages/server/src/types.ts

@@ -82,7 +82,7 @@ export type AgentModeType = 'build' | 'plan';
 
 // 客户端发送的消息
 export interface ClientMessage {
-  type: 'message' | 'cancel' | 'tool_response' | 'permission_response' | 'config_update' | 'mode_switch' | 'user_input_response';
+  type: 'message' | 'cancel' | 'tool_response' | 'permission_response' | 'config_update' | 'mode_switch' | 'user_input_response' | 'system_command';
   sessionId: string;
   payload?: {
     content?: string;
@@ -122,7 +122,9 @@ export interface ServerMessage {
     | 'subagent:end'        // 子 Agent 执行结束
     | 'subagent:stream'     // 子 Agent 流式输出
     | 'subagent:tool_start' // 子 Agent 工具调用开始
-    | 'subagent:tool_end';  // 子 Agent 工具调用结束
+    | 'subagent:tool_end'   // 子 Agent 工具调用结束
+    // 系统命令响应
+    | 'system_command_result'; // 系统命令执行结果
   sessionId: string;
   payload?: unknown;
 }

packages/server/src/ws.ts

@@ -6,9 +6,18 @@
 
 import type { WSContext } from 'hono/ws';
 import { getSessionManager } from './session/manager.js';
-import { processMessage, cancelProcessing, getOrCreateAgent, submitUserInput } from './agent/index.js';
+import { processMessage, cancelProcessing, getOrCreateAgent, submitUserInput, clearAgentHistory } from './agent/index.js';
 import { handlePermissionResponse, setSessionAutoApprove } from './permission/handler.js';
 import type { ClientMessage, ServerMessage } from './types.js';
+import {
+  isSystemCommand,
+  executeSystemCommand,
+  initializeSystemCommands,
+  MessageStorage,
+} from '@ai-assistant/core';
+
+// 初始化系统命令
+initializeSystemCommands();
 
 // 存储活跃的 WebSocket 连接
 const connections: Map<string, Set<WSContext>> = new Map();
@@ -109,6 +118,12 @@ export async function handleWebSocketMessage(
         const agentMode = message.payload?.agentMode as 'build' | 'plan' | undefined;
         const autoApprove = message.payload?.autoApprove as boolean | undefined;
 
+        // 检测系统命令（: 前缀）
+        if (isSystemCommand(content)) {
+          await handleSystemCommand(sessionId, content);
+          break;
+        }
+
         // 将 @filepath 转换为 ./filepath 格式（方便 AI 识别为文件路径）
         content = content.replace(/@([\w./-]+)/g, './$1');
 
@@ -281,3 +296,45 @@ export function getConnectionStats(): { sessions: number; connections: number }
     connections: totalConnections,
   };
 }
+
+/**
+ * 处理系统命令（: 前缀）
+ */
+async function handleSystemCommand(sessionId: string, content: string): Promise<void> {
+  const sessionManager = getSessionManager();
+
+  console.log(`[WS] System command: ${content}`);
+
+  // 执行系统命令
+  const result = await executeSystemCommand(content, { sessionId });
+
+  // 处理特殊操作
+  if (result.success && result.action) {
+    switch (result.action.type) {
+      case 'clear_messages': {
+        // 清空存储的消息
+        await MessageStorage.removeBySession(sessionId);
+
+        // 清空 Agent 内存中的对话历史
+        clearAgentHistory(sessionId);
+
+        // 重置会话状态
+        sessionManager.updateStatus(sessionId, 'idle');
+        break;
+      }
+      // 可以在这里添加其他操作类型的处理
+    }
+  }
+
+  // 发送结果给客户端
+  broadcastToSession(sessionId, {
+    type: 'system_command_result',
+    sessionId,
+    payload: {
+      success: result.success,
+      message: result.message,
+      error: result.error,
+      action: result.action,
+    },
+  });
+}