feat: allow backend URL override via env var

frontend/src/utils/configLoader.js

@@ -137,6 +137,16 @@ export const getApiConfig = () => {
         throw new Error('Configuration not loaded. Call loadConfig() first.');
     }
 
+    // Check for environment variable override
+    if (process.env.REACT_APP_BACKEND_URL) {
+        const backendUrl = process.env.REACT_APP_BACKEND_URL.replace(/\/$/, ''); // Remove trailing slash if present
+        console.log('ConfigLoader: Using backend URL from env:', backendUrl);
+        return {
+            videoProcessingEndpoint: `${backendUrl}/api/process`,
+            chunkedUploadEndpoint: backendUrl
+        };
+    }
+
     return cachedConfig.api || {};
 };