feat(ai-agent): 新增AI智能体通用支持框架

1.  新增多语言文案，适配AI智能体通用场景
2.  新增AI智能体页面路由常量与跳转逻辑
3.  改造AI聊天页面支持动态agent_id和页面标题
4.  升级AI服务层，支持多agent_id自动传递

lang/en-us/ai-chat/index.js

@@ -136,4 +136,8 @@ export const lang = {
 	logInitNavbarFailed: 'Failed to initialize navigation bar',
 	logChatComponentNotInit: 'Chat component not initialized',
 	logServicerConfigNotLoaded: '[AI Customer Service] servicerConfig not loaded, retrying after 200ms...'
-}
+
+	// ====== AI Agent general copy (customer service is the first agent) ======
+	aiAgentDefaultTitle: 'AI Agent',
+	aiAgentOpenFailed: 'Failed to open AI Agent, please try again later',
+	aiAgentNotConfigured: 'This AI Agent is not enabled'}