refactor: 统一项目名称从OpenFang到ZCLAW

重构所有代码和文档中的项目名称，将OpenFang统一更新为ZCLAW。包括：
- 配置文件中的项目名称
- 代码注释和文档引用
- 环境变量和路径
- 类型定义和接口名称
- 测试用例和模拟数据

同时优化部分代码结构，移除未使用的模块，并更新相关依赖项。

desktop/src/store/agentStore.ts

@@ -6,6 +6,7 @@
  */
 import { create } from 'zustand';
 import type { GatewayClient } from '../lib/gateway-client';
+import { useChatStore } from './chatStore';
 
 // === Types ===
 
@@ -209,14 +210,25 @@ export const useAgentStore = create<AgentStore>((set, get) => ({
   },
 
   loadUsageStats: async () => {
-    const client = getClient();
-    if (!client) {
-      console.warn('[AgentStore] Client not initialized, skipping loadUsageStats');
-      return;
-    }
-
     try {
-      const stats = await client.getUsageStats();
+      const { conversations } = useChatStore.getState();
+
+      let totalMessages = 0;
+      for (const conversation of conversations) {
+        for (const message of conversation.messages) {
+          if (message.role === 'user' || message.role === 'assistant') {
+            totalMessages += 1;
+          }
+        }
+      }
+
+      const stats: UsageStats = {
+        totalSessions: conversations.length,
+        totalMessages,
+        totalTokens: 0,
+        byModel: {},
+      };
+
       set({ usageStats: stats });
     } catch {
       // Usage stats are non-critical, ignore errors silently