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.

app/components/content/ProseImg.vue

@@ -5,7 +5,7 @@ defineProps<{ src: string, label: string, caption?: string }>()
 <template>
   <div class="flex flex-col justify-center items-center prose-none my-8">
     <img :src="src" :alt="label" class="w-full h-auto m-0 prose-none">
-    <p class="text-sm text-gray-500 dark:text-gray-300 prose-none">
+    <p class="mt-2 text-sm text-gray-500 dark:text-gray-300 prose-none">
       {{ caption }}
     </p>
   </div>