feat: warn on uncertain episode availability

templates/watch.gohtml

@@ -16,6 +16,23 @@
 {{$rangeStart := episodeRangeStart $currentEpNum 100}}
 {{$rangeEnd := min (add $rangeStart 99) $totalEpisodes}}
 
+{{if .EpisodeAvailabilityWarning}}
+<div data-episode-availability-warning class="fixed inset-0 z-100 flex items-center justify-center bg-black/70 px-4" role="dialog" aria-modal="true" aria-labelledby="episode-availability-warning-title">
+  <div class="w-full max-w-md bg-background shadow-card ring-1 ring-black/10">
+    <div class="border-b border-border-light px-5 py-4">
+      <h2 id="episode-availability-warning-title" class="text-base font-medium text-foreground">Episode availability is uncertain</h2>
+    </div>
+    <div class="flex flex-col gap-4 px-5 py-5">
+      <p class="text-sm leading-6 text-foreground-muted">{{.EpisodeAvailabilityWarning}}</p>
+      <div class="flex justify-end gap-3">
+        <a href="/anime/{{$anime.MalID}}" class="inline-flex items-center justify-center bg-background-button px-4 py-2 text-sm text-foreground-muted transition-colors hover:bg-background-button-hover hover:text-foreground focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-accent">Go back</a>
+        <button type="button" data-episode-availability-warning-continue class="inline-flex items-center justify-center bg-accent px-4 py-2 text-sm text-white transition-opacity hover:opacity-90 focus-visible:outline-none focus-visible:ring-1 focus-visible:ring-accent">Continue anyway</button>
+      </div>
+    </div>
+  </div>
+</div>
+{{end}}
+
 <div id="watch-layout" class="flex h-full flex-col gap-6 overflow-y-auto lg:grid lg:grid-cols-[minmax(0,min(calc(100%_-_24rem_-_3rem),calc((100dvh-10.5rem)*16/9)))_24rem] lg:items-start lg:gap-x-12 lg:gap-y-0 lg:overflow-hidden">
   <div class="min-w-0">
     <div id="video-player-container">