feat(ui): refine post interaction surfaces

components/post-like-button.tsx

@@ -22,8 +22,9 @@ export function PostLikeButton({ postId, initialLiked, initialLikeCount }: PostL
   return (
     <button
       type="button"
+      aria-label={liked ? "取消点赞帖子" : "点赞帖子"}
       disabled={pending}
-      className="flex items-center gap-1 hover:text-foreground transition-colors disabled:opacity-60 disabled:pointer-events-none"
+      className="flex items-center gap-1 text-muted-foreground transition-colors hover:text-foreground disabled:pointer-events-none disabled:opacity-60"
       onClick={() =>
         requireAuth(() => {
           if (pending) return
@@ -52,7 +53,7 @@ export function PostLikeButton({ postId, initialLiked, initialLikeCount }: PostL
         })
       }
     >
-      <Heart className={`h-4 w-4 ${liked ? "fill-red-500 text-red-500" : ""}`} />
+      <Heart className={`h-4 w-4 ${liked ? "fill-destructive text-destructive" : ""}`} />
       {likeCount}
     </button>
   )