feat: add homepage, content collections, and utils

- Homepage with hero, featured projects, latest posts sections
- Content collections config (blog + projects schemas)
- Date formatting and reading time utilities
- Sample blog post and project for validation

src/utils/readingTime.ts

@@ -0,0 +1,6 @@
+export function getReadingTime(content: string): string {
+  const wordsPerMinute = 200;
+  const words = content.trim().split(/\s+/).length;
+  const minutes = Math.ceil(words / wordsPerMinute);
+  return `${minutes} min lectura`;
+}