First pass

src/pages/api/auth/logout.ts

@@ -0,0 +1,11 @@
+import type { APIRoute } from 'astro';
+import { invalidateSession } from '../../../lib/auth';
+
+export const POST: APIRoute = async ({ cookies, redirect }) => {
+  const sessionId = cookies.get('session_id')?.value;
+  if (sessionId) {
+    await invalidateSession(sessionId);
+    cookies.delete('session_id', { path: '/' });
+  }
+  return redirect('/login');
+};