Add multi-language audio tracks and self-hosted flag-icons

Introduce per-video language support and multiple audio tracks
(VideoAudioTrack model + migrations for language, description, title),
a reusable language-select component, and a track-editor form. Bundle
the self-hosted flag-icons v7.2.3 library and a NAS auto-sync command.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>

resources/views/components/playlist-card.blade.php

@@ -1,5 +1,13 @@
 @props(['playlist'])
 
+@php
+    $pl        = $playlist;
+    $firstVid  = $pl->videos->first();
+    $plUrl     = $firstVid
+        ? route('videos.show', $firstVid) . '?playlist=' . $pl->share_token
+        : route('playlists.show', $pl->id);
+@endphp
+
 @once
 <style>
 .pl-count-badge {
@@ -59,10 +67,8 @@
 </style>
 @endonce
 
-@php $pl = $playlist; @endphp
-
 <div class="yt-video-card">
-    <a href="{{ route('playlists.show', $pl->id) }}">
+    <a href="{{ $plUrl }}">
         <div class="yt-video-thumb">
             <img src="{{ $pl->thumbnail_url }}" alt="{{ $pl->name }}" loading="lazy" decoding="async" onload="this.classList.add('loaded');this.closest('.yt-video-thumb').classList.add('loaded')">
             <div class="pl-count-badge">
@@ -94,7 +100,7 @@
         </div>
         <div class="yt-video-details">
             <h3 class="yt-video-title">
-                <a href="{{ route('playlists.show', $pl->id) }}">{{ $pl->name }}</a>
+                <a href="{{ $plUrl }}">{{ $pl->name }}</a>
             </h3>
             @if($pl->user)
                 <a href="{{ route('channel', $pl->user->channel) }}" class="yt-channel-name"