Initial commit — AI-powered coding tutor (Professor)

Next.js 16, React 19, Monaco editor, Anthropic SDK, multi-provider AI,
Wandbox Python execution, iframe HTML preview, SQLite auth + session persistence.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app/api/auth/logout/route.ts

@@ -0,0 +1,7 @@
+import { NextResponse } from 'next/server';
+import { clearAuthCookie } from '@/lib/auth';
+
+export async function POST() {
+  await clearAuthCookie();
+  return NextResponse.json({ ok: true });
+}