refactor: Remove https-proxy-agent dependency and related code from proxy route

app/api/proxy/route.ts

@@ -1,5 +1,4 @@
 import { NextRequest, NextResponse } from 'next/server';
-import { HttpsProxyAgent } from 'https-proxy-agent';
 
 export async function GET(request: NextRequest) {
     const url = request.nextUrl.searchParams.get('url');
@@ -12,10 +11,6 @@ export async function GET(request: NextRequest) {
         // Beijing IP address to simulate request from China
         const chinaIP = '202.108.22.5';
 
-        // Configure proxy agent if environment variable is set
-        const proxyUrl = process.env.CHINA_PROXY_URL;
-        const agent = proxyUrl ? new HttpsProxyAgent(proxyUrl) : undefined;
-
         const response = await fetch(url, {
             headers: {
                 'User-Agent': 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
@@ -23,8 +18,6 @@ export async function GET(request: NextRequest) {
                 'Client-IP': chinaIP,
                 'Referer': new URL(url).origin,
             },
-            // @ts-ignore - node-fetch types don't perfectly match Next.js fetch extension
-            agent: agent,
         });
 
         const contentType = response.headers.get('Content-Type');