docker-compose: build both images from source, bake frontend into nginx, use --build flag

frontend/index.html

@@ -478,7 +478,7 @@
 </div>
 
 <script>
-const API = 'http://10.10.11.103/api';
+const API = '/api';
 let projects = [];
 let currentFilter = 'all';
 let editingId = null;