feat: add teacher-facing frontend

frontend/src/api.ts

@@ -0,0 +1,11 @@
+export async function api(path: string, method = 'GET', body?: unknown): Promise<any> {
+  const response = await fetch('/api' + path, { method, headers: body === undefined ? {} : { 'Content-Type': 'application/json' }, body: body === undefined ? undefined : JSON.stringify(body) });
+  if (!response.ok) {
+    let detail = response.statusText;
+    try { const value = await response.json(); detail = typeof value.detail === 'string' ? value.detail : JSON.stringify(value.detail); } catch { /* server returned no JSON */ }
+    throw new Error(detail);
+  }
+  return response.json();
+}
+export const post = (path: string, body?: unknown) => api(path, 'POST', body);
+export const put = (path: string, body: unknown) => api(path, 'PUT', body);