Polish mobile layouts, extract ExpandableText, fix image sizing

- Stack title-hero poster/metadata vertically on mobile (flex-col md:flex-row),
  switch backdrop tall breakpoint from sm to md
- Extract bio expand/collapse logic into reusable ExpandableText component;
  use it in PersonHero and TitleHero
- Fix ContinueWatchingCard image to use fill + sizes instead of fixed
  width/height to avoid layout shift
- Add fade-out gradient on genre chip scrollbar edge on mobile
- Show scaled-down ambient glow on mobile instead of hiding it entirely
- Humanize knownForDepartment labels (Acting→Actor, Directing→Director, etc.)
- Change cast member name from truncate to line-clamp-2 for wrapping
- Hide tooltip arrow via [&>:last-child]:hidden instead of color-matching it
- Apply safe-area-inset padding to HeroBanner content on notched devices

components/ui/skeleton.tsx

@@ -4,7 +4,7 @@ function Skeleton({ className, ...props }: React.ComponentProps<"div">) {
   return (
     <div
       data-slot="skeleton"
-      className={cn("bg-muted animate-pulse rounded-md", className)}
+      className={cn("animate-pulse rounded-md bg-muted", className)}
       {...props}
     />
   );