feat: initialize Astro project with Tailwind and TypeScript

- Astro 5.0 with TypeScript strict mode
- Tailwind CSS 3.4 configured with custom design system
- Project structure created (components, layouts, content, styles)
- Sitemap and RSS integrations added
- Build verified successfully

Fixes dependency conflict by using Astro 5 instead of 6

astro.config.mjs

@@ -0,0 +1,16 @@
+import { defineConfig } from 'astro/config';
+import tailwind from '@astrojs/tailwind';
+import sitemap from '@astrojs/sitemap';
+
+export default defineConfig({
+  site: 'https://davidaragon.impresion3d.pro',
+  integrations: [
+    tailwind(),
+    sitemap(),
+  ],
+  markdown: {
+    shikiConfig: {
+      theme: 'dark-plus',
+    },
+  },
+});