Add API endpoints for content and update MCP resources to use them

Co-authored-by: ArthurDanjou <29738535+ArthurDanjou@users.noreply.github.com>

server/api/uses.get.ts

@@ -0,0 +1,19 @@
+export default defineEventHandler(async (event) => {
+  const categories = await queryCollection(event, 'usesCategories')
+    .where('extension', '=', 'md')
+    .all()
+
+  const uses = await queryCollection(event, 'uses')
+    .where('extension', '=', 'md')
+    .all()
+
+  const uses_by_categories = []
+  for (const category of categories) {
+    uses_by_categories.push({
+      category: category,
+      uses: uses.filter((use: { category: unknown }) => use.category === category.slug)
+    })
+  }
+
+  return uses_by_categories
+})