Refactor navigation links to use Next.js routing and improve post handling

- Updated AboutButton to navigate to the about page using Next.js router.
- Changed HeaderButtons and MobileNav to link directly to the about page.
- Modified Home component to exclude the 'about' post from the posts list.
- Added a helper function to strip YAML frontmatter from post summaries.
- Enhanced API routes to handle reading and writing markdown files for posts.

posts/about.md

@@ -0,0 +1,30 @@
+---
+title: About Me
+date: 2025-07-04
+tags: [about, profile]
+author: rattatwinko
+summary: This is the about page
+---
+# About Me
+
+Hi! I'm Rattatwinko, a passionate developer who loves building self-hosted tools and beautiful web experiences.
+
+![](assets/peta.png)
+
+## Skills
+- TypeScript, JavaScript
+- Rust
+- React, Next.js
+- Tailwind CSS
+- Docker
+
+## Experience
+- Indie developer, 2020–present
+- Open source contributor
+
+## Projects
+- **MarkdownBlog**: The site you're reading now! A fast, modern, and hackable markdown blog platform.
+
+## Contact
+- [GitHub](https://github.com/rattatwinko)
+- [Email](mailto:me@example.com)