Add folder and post details fetching in ManagePage; implement delete confirmation modal for folders with recursive deletion option in API.

src/app/api/admin/posts/size/route.ts

@@ -0,0 +1,18 @@
+import { NextResponse } from 'next/server';
+import fs from 'fs';
+import path from 'path';
+
+const postsDirectory = path.join(process.cwd(), 'posts');
+
+export async function GET(request: Request) {
+  const { searchParams } = new URL(request.url);
+  const slug = searchParams.get('slug');
+  if (!slug) return NextResponse.json({ size: null, created: null });
+  try {
+    const filePath = path.join(postsDirectory, `${slug}.md`);
+    const stat = fs.statSync(filePath);
+    return NextResponse.json({ size: stat.size, created: stat.birthtime.toISOString() });
+  } catch {
+    return NextResponse.json({ size: null, created: null });
+  }
+}