fix: use untrack() in \$state initialisers to silence state_referenced_locally warnings

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/frontend/src/routes/admin/videos/+page.svelte

@@ -1,4 +1,5 @@
 <script lang="ts">
+  import { untrack } from "svelte";
   import { goto, invalidateAll } from "$app/navigation";
   import { page } from "$app/state";
   import { SvelteURLSearchParams } from "svelte/reactivity";
@@ -17,7 +18,7 @@
   let deleteTarget: Video | null = $state(null);
   let deleteOpen = $state(false);
   let deleting = $state(false);
-  let searchValue = $state(data.search ?? "");
+  let searchValue = $state(untrack(() => data.search ?? ""));
   $effect(() => { searchValue = data.search ?? ""; });
   let searchTimeout: ReturnType<typeof setTimeout>;