feat: use env for api endpoint

src/routes/+page.svelte

@@ -1,4 +1,6 @@
 <script>
+	import { PUBLIC_FRESHGUARD_ENDPOINT } from '$env/static/public';
+
 	/**
 	 * @type {HTMLVideoElement | null}
 	 */
@@ -39,7 +41,9 @@
 		formData.append('file', blob, 'image.jpg');
 
 		// Upload to API with form-data format
-		let res = await fetch('http://localhost:5000/predict', {
+		let endpoint = new URL(PUBLIC_FRESHGUARD_ENDPOINT);
+		endpoint.pathname = '/predict';
+		let res = await fetch(endpoint, {
 			method: 'POST',
 			body: formData
 		});