fix(ui): correctly pass BASE_PATH to ui

packages/ui/svelte.config.js

@@ -1,6 +1,8 @@
 import adapter from '@sveltejs/adapter-static';
 import { vitePreprocess } from '@sveltejs/vite-plugin-svelte';
 
+const { BASE_URL = '' } = process.env;
+
 /** @type {import('@sveltejs/kit').Config} */
 const config = {
   // Consult https://kit.svelte.dev/docs/integrations#preprocessors
@@ -8,6 +10,9 @@ const config = {
   preprocess: vitePreprocess(),
 
   kit: {
+    paths: {
+      base: BASE_URL === '/' ? '' : BASE_URL
+    },
     // adapter-auto only supports some environments, see https://kit.svelte.dev/docs/adapter-auto for a list.
     // If your environment is not supported, or you settled on a specific environment, switch out the adapter.
     // See https://kit.svelte.dev/docs/adapters for more information about adapters.