fix(聊天): 添加用户认证和 API Key 解密

- 聊天前检查用户登录状态
- 获取当前用户的设置和 API Key
- 使用时解密 API Key
- 优化未配置 API Key 的错误提示

src/app/api/chat/route.ts

@@ -4,6 +4,8 @@ import { conversations, messages, userSettings } from '@/drizzle/schema';
 import { eq } from 'drizzle-orm';
 import { nanoid } from 'nanoid';
 import { executeTool } from '@/services/tools';
+import { getCurrentUser } from '@/lib/auth';
+import { decryptApiKey } from '@/lib/crypto';
 
 interface ChatRequest {
   conversationId: string;
@@ -212,18 +214,30 @@ export async function POST(request: Request) {
       })) : undefined,
     });
 
-    // 获取用户设置
+    // 获取当前登录用户
+    const user = await getCurrentUser();
+    if (!user) {
+      return NextResponse.json(
+        { error: '请先登录后再使用聊天功能' },
+        { status: 401 }
+      );
+    }
+
+    // 获取该用户的设置
     const settings = await db.query.userSettings.findFirst({
-      where: eq(userSettings.id, 1),
+      where: eq(userSettings.userId, user.userId),
     });
 
     if (!settings?.cchApiKey) {
       return NextResponse.json(
-        { error: 'Please configure your CCH API key in settings' },
+        { error: '请先在设置中配置您的 API Key 才能使用聊天功能', code: 'API_KEY_NOT_CONFIGURED' },
         { status: 400 }
       );
     }
 
+    // 解密 API Key
+    const decryptedApiKey = decryptApiKey(settings.cchApiKey);
+
     // 获取对话信息
     const conversation = await db.query.conversations.findFirst({
       where: eq(conversations.conversationId, conversationId),
@@ -267,7 +281,7 @@ export async function POST(request: Request) {
     const stream = new ReadableStream({
       async start(controller) {
         try {
-          const cchUrl = settings.cchUrl || 'http://localhost:13500';
+          const cchUrl = settings.cchUrl || process.env.CCH_DEFAULT_URL || 'https://claude.leocoder.cn/';
 
           // 获取系统提示词（叠加模式）
           // 1. 始终使用 DEFAULT_SYSTEM_PROMPT 作为基础
@@ -302,7 +316,7 @@ export async function POST(request: Request) {
             // ==================== Codex 模型处理（OpenAI 格式） ====================
             const result = await handleCodexChat({
               cchUrl,
-              apiKey: settings.cchApiKey!,
+              apiKey: decryptedApiKey,
               model: useModel,
               systemPrompt,
               temperature,
@@ -321,7 +335,7 @@ export async function POST(request: Request) {
             // ==================== Claude 模型处理（原有逻辑） ====================
             const result = await handleClaudeChat({
               cchUrl,
-              apiKey: settings.cchApiKey!,
+              apiKey: decryptedApiKey,
               model: useModel,
               systemPrompt,
               temperature,