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

lib/imgproxy-loader.ts

@@ -0,0 +1,27 @@
+import { getImgproxyUrl } from './imgproxy';
+
+/**
+ * Next.js Image Loader for imgproxy
+ *
+ * @param {Object} props - properties from Next.js Image component
+ * @param {string} props.src - The source image URL
+ * @param {number} props.width - The desired image width
+ * @param {number} props.quality - The desired image quality (ignored for now as imgproxy handles it)
+ */
+export default function imgproxyLoader({
+  src,
+  width,
+  _quality,
+}: {
+  src: string;
+  width: number;
+  _quality?: number;
+}) {
+  // We use the width provided by Next.js for responsive images
+  // Height is set to 0 to maintain aspect ratio
+  return getImgproxyUrl(src, {
+    width,
+    resizing_type: 'fit',
+    gravity: 'fv', // Use face-aware focusing (face detection)
+  });
+}