fix: prefer-arrow-callback ESLint rule and Prettier formatting

Convert TypingIndicator named function expression to arrow function to
satisfy prefer-arrow-callback lint rule. Auto-format RoomInput.tsx to
resolve Prettier check failures in CI.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/app/components/typing-indicator/TypingIndicator.tsx

@@ -10,7 +10,7 @@ export type TypingIndicatorProps = {
 };
 
 export const TypingIndicator = as<'div', TypingIndicatorProps>(
-  function TypingIndicatorInner({ size, disableAnimation, style, ...props }, ref) {
+  ({ size, disableAnimation, style, ...props }, ref) => {
     const [lotusTerminal] = useSetting(settingsAtom, 'lotusTerminal');
     return (
       <Box

src/app/features/room/RoomInput.tsx

@@ -151,7 +151,9 @@ export const RoomInput = forwardRef<HTMLDivElement, RoomInputProps>(
     const creators = useRoomCreators(room);
 
     const [charCount, setCharCount] = useState(0);
-    useEffect(() => { setCharCount(0); }, [roomId]);
+    useEffect(() => {
+      setCharCount(0);
+    }, [roomId]);
 
     const alive = useAlive();
     const [msgDraft, setMsgDraft] = useAtom(roomIdToMsgDraftAtomFamily(roomId));