style: 将本pr涉及的代码（主要是AI模块）内的注释改成中文，便于协作

Author: Crokily

app/api/chat/route.ts

@@ -2,13 +2,13 @@ import { streamText, UIMessage, convertToModelMessages } from "ai";
 import { getModel, requiresApiKey, type AIProvider } from "@/lib/ai/models";
 import { buildSystemMessage } from "@/lib/ai/prompt";
 
-// Allow streaming responses up to 30 seconds
+// 流式响应最长30秒
 export const maxDuration = 30;
 
 interface ChatRequest {
   messages: UIMessage[];
-  system?: string; // System message forwarded from AssistantChatTransport
-  tools?: unknown; // Frontend tools forwarded from AssistantChatTransport
+  system?: string;
+  tools?: unknown;
   pageContext?: {
     title?: string;
     description?: string;
@@ -25,11 +25,11 @@ export async function POST(req: Request) {
       messages,
       system,
       pageContext,
-      provider = "openai", // Default to OpenAI
+      provider = "intern", // 默认使用书生模型
       apiKey,
     }: ChatRequest = await req.json();
 
-    // Validate API key for providers that require it
+    // 对指定Provider验证key是否存在
     if (requiresApiKey(provider) && (!apiKey || apiKey.trim() === "")) {
       return Response.json(
         {
@@ -40,13 +40,13 @@ export async function POST(req: Request) {
       );
     }
 
-    // Build system message with page context
+    // 构建系统消息，包含页面上下文
     const systemMessage = buildSystemMessage(system, pageContext);
 
-    // Get AI model instance based on provider
+    // 根据Provider获取 AI 模型实例
     const model = getModel(provider, apiKey);
 
-    // Generate streaming response
+    // 生成流式响应
     const result = streamText({
       model: model,
       system: systemMessage,
@@ -57,7 +57,7 @@ export async function POST(req: Request) {
   } catch (error) {
     console.error("Chat API error:", error);
 
-    // Handle specific model creation errors
+    // 处理特定模型创建错误
     if (error instanceof Error && error.message.includes("API key")) {
       return Response.json({ error: error.message }, { status: 400 });
     }

lib/ai/models.ts

@@ -5,10 +5,10 @@ import { createInternModel } from "./providers/intern";
 export type AIProvider = "openai" | "gemini" | "intern";
 
 /**
- * Model factory that returns the appropriate AI model based on provider
- * @param provider - The AI provider to use
- * @param apiKey - API key (not required for intern provider)
- * @returns Configured AI model instance
+ * Model工厂 用于返回对应的 AI 模型实例
+ * @param provider - 要用的provider
+ * @param apiKey - API key (intern provider不需要用户提供 API key)
+ * @returns 配置好的 AI 模型实例
  */
 export function getModel(provider: AIProvider, apiKey?: string) {
   switch (provider) {
@@ -25,7 +25,7 @@ export function getModel(provider: AIProvider, apiKey?: string) {
       return createGeminiModel(apiKey);
 
     case "intern":
-      // Intern provider doesn't need API key from user
+      // Intern 书生模型不需要用户提供 API key
       return createInternModel();
 
     default:
@@ -34,9 +34,9 @@ export function getModel(provider: AIProvider, apiKey?: string) {
 }
 
 /**
- * Check if the given provider requires an API key from the user
- * @param provider - The AI provider to check
- * @returns True if API key is required, false otherwise
+ * 检查指定的提供者是否需要用户提供 API key
+ * @param provider - 要检查的provider
+ * @returns 如果需要 API key，返回 true，否则返回 false
  */
 export function requiresApiKey(provider: AIProvider): boolean {
   return provider !== "intern";

lib/ai/prompt.ts

@@ -6,23 +6,23 @@ interface PageContext {
 }
 
 /**
- * Build system message with page context for AI assistant
- * @param customSystem - Custom system message (optional)
- * @param pageContext - Current page context (optional)
- * @returns Complete system message string
+ * 构建系统消息，包含页面上下文
+ * @param customSystem - 自定义系统消息 (可选)
+ * @param pageContext - 当前页面上下文 (可选)
+ * @returns 完整的系统消息字符串
  */
 export function buildSystemMessage(
   customSystem?: string,
   pageContext?: PageContext,
 ): string {
-  // Default system message for documentation assistant
+  // 默认系统消息
   let systemMessage =
     customSystem ||
     `You are a helpful AI assistant for a documentation website. 
     You can help users understand the documentation, answer questions about the content, 
     and provide guidance on the topics covered in the docs. Be concise and helpful.`;
 
-  // Add current page context if available
+  // 如果当前页面上下文可用，则添加到系统消息中
   if (pageContext?.content) {
     systemMessage += `\n\n--- CURRENT PAGE CONTEXT ---\n`;