Implement environment variable setup for frontend; create .env.production and .env.development files if they don't exist, and update API URLs in frontend components to use dynamic API_BASE_URL for improved configuration management.

frontend/src/views/WeekOverview.vue

@@ -233,7 +233,7 @@ const loadWeekData = async () => {
   try {
     loading.value = true
     
-    const response = await fetch(`http://localhost:3010/api/week-overview?weekOffset=${weekOffset.value}`, {
+    const response = await fetch(`${API_URL}/week-overview?weekOffset=${weekOffset.value}`, {
       headers: {
         'Authorization': `Bearer ${authStore.token}`,
         'Content-Type': 'application/json'