Convert dangrubb.net to Astro framework

- Migrated main site, blog, CV, and music sections to Astro
- Component-based architecture with layouts
- JSON-based blog posts
- Static site generation
- Preserved original styling and functionality

astro.config.mjs

@@ -0,0 +1,9 @@
+import { defineConfig } from 'astro/config';
+
+export default defineConfig({
+  site: 'https://dangrubb.net',
+  output: 'static',
+  build: {
+    assets: 'assets'
+  }
+});