featmigrate from Angular to Astro static site

BREAKING CHANGE: Complete rewrite from Angular SPA to Astro

- Replace Angular 18 with Astro 5.16.7 + Tailwind CSS
- Convert all Angular components to Astro components
- Add content collections for blog with markdown support
- Setup S3 deployment with CloudFront invalidation
- Add RSS feed and sitemap generation
- Configure Prettier and Biome for code formatting
- Switch from npm to pnpm
- Remove Amplify backend (now fully static)
- Improve SEO and performance with static generation

.env

@@ -1 +1,8 @@
-PERFORMANCE_PROFILER=true
+# OpenWeatherMap API Key
+# Get your free API key at: https://openweathermap.org/api
+# Free tier includes 1,000 API calls per day
+PUBLIC_OPENWEATHER_API_KEY=0938949580094b5d165c2e7cd23b7cf2
+
+# Weather Location Configuration
+PUBLIC_WEATHER_CITY=Rome
+PUBLIC_WEATHER_COUNTRY_CODE=IT