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

src/assets/linkedin.svg

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8"?><!-- Uploaded to: SVG Repo, www.svgrepo.com, Generator: SVG Repo Mixer Tools -->
+<svg width="800px" height="800px" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg">
+<path d="M6.5 8C7.32843 8 8 7.32843 8 6.5C8 5.67157 7.32843 5 6.5 5C5.67157 5 5 5.67157 5 6.5C5 7.32843 5.67157 8 6.5 8Z" fill="#0F0F0F"/>
+<path d="M5 10C5 9.44772 5.44772 9 6 9H7C7.55228 9 8 9.44771 8 10V18C8 18.5523 7.55228 19 7 19H6C5.44772 19 5 18.5523 5 18V10Z" fill="#0F0F0F"/>
+<path d="M11 19H12C12.5523 19 13 18.5523 13 18V13.5C13 12 16 11 16 13V18.0004C16 18.5527 16.4477 19 17 19H18C18.5523 19 19 18.5523 19 18V12C19 10 17.5 9 15.5 9C13.5 9 13 10.5 13 10.5V10C13 9.44771 12.5523 9 12 9H11C10.4477 9 10 9.44772 10 10V18C10 18.5523 10.4477 19 11 19Z" fill="#0F0F0F"/>
+<path fill-rule="evenodd" clip-rule="evenodd" d="M20 1C21.6569 1 23 2.34315 23 4V20C23 21.6569 21.6569 23 20 23H4C2.34315 23 1 21.6569 1 20V4C1 2.34315 2.34315 1 4 1H20ZM20 3C20.5523 3 21 3.44772 21 4V20C21 20.5523 20.5523 21 20 21H4C3.44772 21 3 20.5523 3 20V4C3 3.44772 3.44772 3 4 3H20Z" fill="#0F0F0F"/>
+</svg>