feat: implement automatic image optimization with Astro Assets

- Configure content collections to use image() helper for type-safe image references
- Replace all <img> tags with <Image> component from astro:assets
- Migrate images from /public to /src/assets for automatic optimization
- Update blog posts to use relative paths in frontmatter (../../assets/photos/)
- Remove unused images and duplicates from /public folder
- Update Footer component to use optimized SVG icons
- Clean up manifest.json to use favicon.ico instead of deleted photos

Performance improvements:
- remote.jpg: 1.8MB → 128KB (93% reduction)
- me.png: 71KB → 12KB (83% reduction)
- Automatic WebP conversion
- Tree-shaking: only used images are optimized

/public folder reduced from 2.3MB to 32KB (only essential files)
Build output: 2.2MB with fully optimized images ready for S3 deployment

astro.config.mjs

@@ -1,11 +1,12 @@
+import mdx from "@astrojs/mdx";
 import sitemap from "@astrojs/sitemap";
 import tailwind from "@astrojs/tailwind";
 import { defineConfig } from "astro/config";
 
 // https://astro.build/config
 export default defineConfig({
-	integrations: [tailwind(), sitemap()],
-	site: "https://lorenzoiovino.com",
+	integrations: [tailwind(), sitemap(), mdx()],
+	site: "https://www.lorenzoiovino.com",
 	compressHTML: true,
 	build: {
 		inlineStylesheets: "auto",