feat: optimize performance and SEO, integrate Lighthouse CI

- Integrated imgproxy for centralized image optimization
- Implemented Lighthouse CI in Gitea pipeline with native Chromium
- Reached 100/100 SEO score by fixing canonicals, hreflang, and link text
- Optimized LCP by forcing Hero component visibility until hydration
- Decoupled analytics into an async shell to reduce TTI

middleware.ts

@@ -1,5 +1,5 @@
 import createMiddleware from 'next-intl/middleware';
-import { NextRequest } from 'next/server';
+import { NextRequest, NextResponse } from 'next/server';
 
 // Create the internationalization middleware
 const intlMiddleware = createMiddleware({
@@ -20,9 +20,10 @@ export default function middleware(request: NextRequest) {
     pathname.startsWith('/errors') ||
     pathname.startsWith('/health') ||
     pathname.includes('/api/og') ||
-    pathname.includes('opengraph-image')
+    pathname.includes('opengraph-image') ||
+    pathname.endsWith('sitemap.xml')
   ) {
-    return;
+    return NextResponse.next();
   }
 
   // Build header object for logging
@@ -93,6 +94,6 @@ export default function middleware(request: NextRequest) {
 
 export const config = {
   matcher: [
-    '/((?!api|_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp|pdf|txt|vcf)$).*)',
+    '/((?!api|_next/static|_next/image|favicon.ico|.*\\.(?:svg|png|jpg|jpeg|gif|webp|pdf|txt|vcf|xml)$).*)',
   ],
 };