Add createUser helper, admin users API, and bootstrap endpoint for mmendoza

src/app/api/admin/users/route.ts

@@ -0,0 +1,23 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { requireRole, createUser } from '@/lib/auth';
+
+export async function POST(request: NextRequest) {
+  try {
+    await requireRole('admin');
+    const body = await request.json();
+    const { username, password, role = 'user' } = body;
+
+    if (!username || !password) {
+      return NextResponse.json({ error: 'Username and password are required' }, { status: 400 });
+    }
+
+    if (role !== 'admin' && role !== 'user') {
+      return NextResponse.json({ error: 'Role must be admin or user' }, { status: 400 });
+    }
+
+    const user = await createUser(username, password, role as 'admin' | 'user');
+    return NextResponse.json({ ok: true, user: { id: user.id, username: user.username, role: user.role } });
+  } catch (err: any) {
+    return NextResponse.json({ error: err.message || 'Failed to create user' }, { status: err.message === 'Unauthorized' ? 401 : 500 });
+  }
+}