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

biome.json

@@ -22,15 +22,27 @@
   },
   "linter": {
     "enabled": true,
+    "domains": {
+      "next": "recommended",
+      "react": "recommended"
+    },
     "rules": {
       "recommended": true,
       "suspicious": {
         "noUnknownAtRules": "off"
+      },
+      "nursery": {
+        "useSortedClasses": {
+          "level": "error",
+          "options": {
+            "attributes": ["classList"],
+            "functions": ["cn", "clsx", "cva"]
+          }
+        },
+        "noFloatingPromises": "error",
+        "noMisusedPromises": "error",
+        "useDestructuring": "error"
       }
-    },
-    "domains": {
-      "next": "recommended",
-      "react": "recommended"
     }
   },
   "assist": {