feat(library): genre sliders, artist links, and navigation utils

- music landing: diverse per-genre album sliders (online counts /
  offline wide-probe fallback) and home-screen library shortcuts
- add ArtistLinks component and shared navigation/genreDiversity utils
- player/playback-mode refinements across Rust and frontend

src/lib/components/library/GenericMediaListPage.svelte

@@ -2,6 +2,7 @@
 <script lang="ts">
   import { onMount } from "svelte";
   import { goto } from "$app/navigation";
+  import { navigateBack } from "$lib/utils/navigation";
   import { currentLibrary } from "$lib/stores/library";
   import { auth } from "$lib/stores/auth";
   import { shouldShowAudioMiniPlayer } from "$lib/stores/player";
@@ -130,7 +131,7 @@
   }
 
   function goBack() {
-    goto(config.backPath);
+    navigateBack(config.backPath);
   }
 
   const searchPlaceholder = $derived(config.searchPlaceholder || `Search ${config.title.toLowerCase()}...`);