feat: add post like

internal/model/social.go

@@ -39,6 +39,13 @@ type Post struct {
 	// after the repo returns posts; always false for anonymous viewers.
 	// Drives the post-card "Reshare ↔ Send" swap on the frontend.
 	ViewerHasReshared bool `json:"viewer_has_reshared"`
+
+	// Likes. LikesCount is the effective total = the denormalized
+	// posts.likes_count plus any still-pending Redis delta (hydrated by the
+	// like layer). ViewerHasLiked reflects the calling user's membership row;
+	// false for anonymous viewers.
+	LikesCount     int  `json:"likes_count"`
+	ViewerHasLiked bool `json:"viewer_has_liked"`
 }
 
 // PostImage represents one attached image on a post.
@@ -167,6 +174,13 @@ type Notification struct {
 	CreatedAt time.Time  `json:"created_at"`
 	ReadAt    *time.Time `json:"read_at,omitempty"`
 
+	// Aggregation: for post_like, PostID is the liked post and ActorCount is
+	// how many likers have aggregated into this single row (the frontend
+	// renders "X and N-1 others liked your post"). Other kinds: PostID nil,
+	// ActorCount 1.
+	PostID     *string `json:"post_id,omitempty"`
+	ActorCount int     `json:"actor_count"`
+
 	ActorName   *string `json:"actor_name,omitempty"`
 	ActorHandle *string `json:"actor_handle,omitempty"`
 	ActorAvatar *string `json:"actor_avatar_url,omitempty"`