feat: improve combination search and offline build

offline/page-store.ts

@@ -0,0 +1,11 @@
+import { writable } from 'svelte/store';
+
+function pageValue(pathname: string) {
+  return { url: new URL(pathname, 'https://offline.holodori.local') };
+}
+
+export const page = writable(pageValue('/'));
+
+export function setOfflinePage(pathname: string) {
+  page.set(pageValue(pathname));
+}