feat: recover portfolio pages from scratch workspaces

- Add base layouts (BaseLayout, BlogLayout, ProjectLayout)
- Add UI components (Header, Footer, Navigation, Card, Tag)
- Add About page with personal story
- Add Projects pages (index, detail)
- Add homepage content
- Add SEO files (robots.txt, webmanifest)

Work was done by agents in isolated workspaces.
Consolidated into main repo for proper git tracking.

src/components/ui/Card.astro

@@ -0,0 +1,17 @@
+---
+export interface Props {
+  href?: string;
+  class?: string;
+}
+
+const { href, class: className } = Astro.props;
+const Component = href ? 'a' : 'div';
+---
+
+<Component 
+  href={href}
+  class={`bg-surface rounded-lg border border-text-tertiary/20 p-6 hover:border-primary/40 
+          transition-colors ${className || ''} ${href ? 'block' : ''}`}
+>
+  <slot />
+</Component>