fix(native/community): sync realtime-patched likes_count back into PostCard

`useCommunityRealtime` was already patching the React-Query cache
on community_posts UPDATE events — likesCount, dislikesCount, userLike
all reached the component as props on re-render. But PostCard was
seeding `localLike` / `localCount` once via useState initial values
and never re-reading the props after mount, so a like from another
account showed up as a notification but the heart counter stayed
stale until pull-to-refresh.

Added a useEffect that mirrors `post.likesCount` / `post.userLike`
back into local state, guarded by `isLiking` so an in-flight
optimistic update isn't clobbered by a concurrent realtime patch
of the same row.

Handles unlike (decrement) on the same path, plus off-screen posts
which get the patched cache value on remount and feed-list cards
that refresh in place without scroll.

apps/rebreak-native/components/PostCard.tsx

@@ -30,6 +30,14 @@ function PostCardImpl({ post, onCommentPress }: Props) {
   const [localCount, setLocalCount] = useState(post.likesCount);
   const [isLiking, setIsLiking] = useState(false);
 
+  // Sync realtime-patched prop values into local state. Guarded by isLiking so
+  // an in-flight optimistic update is never clobbered by a concurrent patch.
+  useEffect(() => {
+    if (isLiking) return;
+    setLocalCount(post.likesCount);
+    setLocalLike(post.userLike === 'like' ? 'like' : null);
+  }, [post.likesCount, post.userLike, isLiking]);
+
   // Heart-Pop Animation — Insta-Style: quick scale-up + spring-bounce back
   const heartScale = useRef(new Animated.Value(1)).current;
   const triggerHeartPop = useCallback(() => {