Refactor: Split portfolio to projects and writings sections, and update content structure

- Renamed 'portfolio' collection to 'projects' in content configuration.
- Introduced a new 'writings' collection with corresponding schema.
- Updated README to reflect changes in content structure and navigation.
- Removed the old portfolio page and added new pages for projects and writings.
- Added multiple new project and writing markdown files with relevant content.
- Updated license year to 2025.
- Enhanced AppHeader for new navigation links.
- Improved ProseImg component styling.

content/projects/artsite.md

@@ -0,0 +1,24 @@
+---
+slug: artsite
+title: 🌍 ArtSite
+description: My personal website, my portfolio, and my blog.
+publishedAt: 2024/06/01
+readingTime: 1
+cover: artsite/cover.png
+tags:
+  - web
+---
+
+[**ArtSite**](https://arthurdanjou.fr) is my personal website, my portfolio, and my blog. It's a place where I can share my projects, my thoughts, and my experiences. It's also a place where I can experiment with new technologies and design ideas.
+
+## ⚒️ Tech stack
+
+- **UI** → [Vue.js](https://vuejs.org/)
+- **Framework** → [Nuxt.js](https://nuxtjs.org/)
+- **Content** → [Nuxt Content](https://content.nuxtjs.org/)
+- **Design System** → [NuxtUI](https://nuxtui.com/)
+- **CMS & Editing** → [Nuxt Studio](https://nuxt.studio)
+- **Langage** → [Typescript](https://www.typescriptlang.org/)
+- **Deployment** → [NuxtHub](https://hub.nuxt.com/)
+- **Styling** → [Sass](https://sass-lang.com/) & [Tailwind CSS](https://tailwindcss.com/)
+- **Package Manager** → [pnpm](https://pnpm.io/)