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/content/projects/sample-project.md

@@ -0,0 +1,21 @@
+---
+title: "Sample Project"
+description: "Test project for content collections validation"
+url: "https://example.com"
+status: "development"
+tags: ["test"]
+startDate: 2026-05-08
+featured: false
+draft: true
+---
+
+# Sample Project
+
+This is a placeholder project to validate content collections.
+
+## Tech Stack
+- Astro
+- TypeScript
+- Tailwind CSS
+
+This will be replaced with real project case studies.