feat(assets): add assets environment variables

Added the environment variables VITE_ASSETS_BUILD_ID for the ID of the
used build and VITE_ASSETS_BASE_URL for the base URL of the assets.
A script for reading this configuration was also added.

.env

@@ -0,0 +1,2 @@
+VITE_ASSETS_BUILD_ID=2026-08-04-76a067e
+VITE_ASSETS_BASE_URL=https://assets.seekra.jcloud-services.ddns.net

src/config/env.js

@@ -0,0 +1,22 @@
+/*
+Copyright 2026 Seekra
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+export const getAssetsUrl = function getAssetsUrl () {
+    return new URL(
+        `${import.meta.env.VITE_ASSETS_BUILD_ID}/`,
+        import.meta.env.VITE_ASSETS_BASE_URL
+    ).href;
+};