fix: limit redirects to browser context

Build breaks because there is no window during server build

src/.vuepress/theme/layouts/Layout.vue

@@ -10,6 +10,9 @@
 export default {
   name: 'Layout',
   beforeCreate() {
+    if (!process.browser) {
+      return;
+    }
     // redirect blog.ipfs.io → blog.ipfs.tech (incl. gateways)
     // https://github.com/ipfs/ipfs-blog/issues/417
     const { href } = window.location