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/textarea.tsx

@@ -7,7 +7,7 @@ function Textarea({ className, ...props }: React.ComponentProps<"textarea">) {
     <textarea
       data-slot="textarea"
       className={cn(
-        "border-input bg-input/20 dark:bg-input/30 focus-visible:border-ring focus-visible:ring-ring/30 aria-invalid:ring-destructive/20 dark:aria-invalid:ring-destructive/40 aria-invalid:border-destructive dark:aria-invalid:border-destructive/50 placeholder:text-muted-foreground flex field-sizing-content min-h-16 w-full resize-none rounded-md border px-2 py-2 text-sm transition-colors outline-none focus-visible:ring-2 disabled:cursor-not-allowed disabled:opacity-50 aria-invalid:ring-2 md:text-xs/relaxed",
+        "field-sizing-content flex min-h-16 w-full resize-none rounded-md border border-input bg-input/20 px-2 py-2 text-sm outline-none transition-colors placeholder:text-muted-foreground focus-visible:border-ring focus-visible:ring-2 focus-visible:ring-ring/30 disabled:cursor-not-allowed disabled:opacity-50 aria-invalid:border-destructive aria-invalid:ring-2 aria-invalid:ring-destructive/20 md:text-xs/relaxed dark:bg-input/30 dark:aria-invalid:border-destructive/50 dark:aria-invalid:ring-destructive/40",
         className,
       )}
       {...props}