Fix public access mode, introduce loading spinners, package fixes

frontend/src/api/client.ts

@@ -1,8 +1,18 @@
 import axios from 'axios';
 
-const apiHost = typeof window !== 'undefined' && window.location.hostname ? window.location.hostname : '127.0.0.1';
-const apiClient = axios.create({
-  baseURL: `http://${apiHost}:8000`,
+const getApiBaseUrl = () => {
+  if (import.meta.env.VITE_API_BASE_URL) {
+    return import.meta.env.VITE_API_BASE_URL;
+  }
+  // Use relative path in browser so requests are routed via Vite proxy or reverse proxy
+  if (typeof window !== 'undefined') {
+    return '';
+  }
+  return 'http://127.0.0.1:8000';
+};
+
+export const apiClient = axios.create({
+  baseURL: getApiBaseUrl(),
   headers: {
     'Content-Type': 'application/json',
   },
@@ -86,3 +96,26 @@ export const getHandbookExample = async (
   });
   return response.data;
 };
+
+export const generateChallenge = async (
+  prompt: string,
+  language: string,
+  difficulty: string,
+  subject: string
+) => {
+  const response = await apiClient.post('/challenges/generate', {
+    prompt,
+    language,
+    difficulty,
+    subject,
+  });
+  return response.data;
+};
+
+export const saveChallenge = async (filename: string, markdown: string) => {
+  const response = await apiClient.post('/challenges/save', {
+    filename,
+    markdown,
+  });
+  return response.data;
+};