feat: post reshare enhancements

internal/model/social.go

@@ -5,6 +5,11 @@ import "time"
 // Post is a public quote on a user's feed. Caption is the verbatim selected
 // text from the knowledgebase; SourceURL links back to the page the user
 // was reading. Images are loaded separately via PostImage rows.
+//
+// Reshares are real Post rows owned by the resharer, with
+// ResharedFromPostID pointing to the canonical original. Likes, comments,
+// and images all hang off the post's own id, so they diverge naturally
+// across reshare boundaries — no parallel "per-resharer" tables.
 type Post struct {
 	ID          string      `json:"id"`
 	UserID      string      `json:"user_id"`
@@ -20,19 +25,20 @@ type Post struct {
 	AuthorHandle    string  `json:"author_handle,omitempty"`
 	AuthorAvatarURL *string `json:"author_avatar_url,omitempty"`
 
-	// ViewerHasReshared is true when the calling user has reshared this
-	// post. Hydrated by the service layer after the repo returns posts;
-	// always false for anonymous viewers (no viewer = no reshare state).
+	// Reshare attribution. ResharedFromPostID is non-nil when this post
+	// is a reshare; the four `Original*` fields carry the canonical
+	// post's author info so the frontend can render a
+	// "Reshared from @handle" link without an extra round-trip.
+	ResharedFromPostID    *string `json:"reshared_from_post_id,omitempty"`
+	OriginalAuthorName    *string `json:"original_author_name,omitempty"`
+	OriginalAuthorHandle  *string `json:"original_author_handle,omitempty"`
+	OriginalAuthorAvatar  *string `json:"original_author_avatar_url,omitempty"`
+
+	// ViewerHasReshared is true when the calling user has reshared the
+	// canonical version of this post. Hydrated by the service layer
+	// 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"`
-
-	// ResharedAt is the timestamp at which the feed owner reshared this
-	// post. Non-nil only for rows that appear in a profile feed because
-	// the profile owner reshared them (i.e. the row comes from the
-	// post_reshares union branch of ListByUser / ListByHandle).
-	// Authored-by-feed-owner rows leave this nil. Drives the
-	// "↻ Reshared" badge in the post card.
-	ResharedAt *time.Time `json:"reshared_at,omitempty"`
 }
 
 // PostImage represents one attached image on a post.