phase 1-6 implemented

apps/mobile/src/config/api.ts

@@ -1,6 +1,27 @@
-export const API_BASE_URL = __DEV__
-  ? "https://fd87cefe27ae.ngrok-free.app"
-  : "https://your-production-url.com";
+// Use environment variable for API URL
+// Set EXPO_PUBLIC_API_URL in your .env file
+const getApiBaseUrl = (): string => {
+  const envUrl = process.env.EXPO_PUBLIC_API_URL;
+
+  if (envUrl) {
+    return envUrl;
+  }
+
+  // Fallback for development if not set
+  if (__DEV__) {
+    console.warn(
+      "EXPO_PUBLIC_API_URL not set in .env - using default localhost",
+    );
+    return "http://localhost:3000";
+  }
+
+  // Production MUST have URL set
+  throw new Error(
+    "EXPO_PUBLIC_API_URL must be set in production environment variables",
+  );
+};
+
+export const API_BASE_URL = getApiBaseUrl();
 
 export const API_ENDPOINTS = {
   AUTH: {