feat(post-api): get_post returns uncapped thumbnails — PostModal masonry needs full image list; feed query unchanged (still capped at 6 for previews). _thumbnails_for gains a limit kwarg; get_post passes limit=None.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

backend/app/services/post_feed_service.py

@@ -109,7 +109,10 @@ class PostFeedService:
         if row is None:
             return None
         post, artist, source = row
-        thumbs_map = await self._thumbnails_for([post.id])
+        # Detail endpoint returns the FULL image list for PostModal's
+        # masonry grid — feed query still caps at THUMBNAIL_LIMIT via
+        # the default arg.
+        thumbs_map = await self._thumbnails_for([post.id], limit=None)
         atts_map = await self._attachments_for([post.id])
         item = self._to_dict(post, artist, source, thumbs_map, atts_map)
         item["description_full"] = html_to_plain(post.description)
@@ -117,15 +120,21 @@ class PostFeedService:
 
     # --- composition helpers ---------------------------------------------
 
-    async def _thumbnails_for(self, post_ids: list[int]) -> dict[int, dict]:
-        """post_id -> {"thumbs": [...up to 6], "more": int}.
+    async def _thumbnails_for(
+        self, post_ids: list[int], *, limit: int | None = THUMBNAIL_LIMIT,
+    ) -> dict[int, dict]:
+        """post_id -> {"thumbs": [...up to limit], "more": int}.
 
-        Selects THUMBNAIL_LIMIT+1 images per post via window function so we
-        can detect overflow in a single query.
+        Selects up to `limit` images per post via window function so we
+        can detect overflow in a single query. Pass `limit=None` to
+        return ALL thumbnails per post (used by `get_post` for PostModal's
+        masonry grid; the feed pass keeps the default cap so payloads
+        stay small).
         """
         if not post_ids:
             return {}
-        # Rank images within each post and fetch only the top THUMBNAIL_LIMIT+1.
+        # Rank images within each post; cap at `limit` rows per post when
+        # limit is set, return all when limit is None.
         ranked = (
             select(
                 ImageRecord.id,
@@ -143,12 +152,13 @@ class PostFeedService:
             .where(ImageRecord.primary_post_id.in_(post_ids))
             .subquery()
         )
-        rows = (await self.session.execute(
-            select(
-                ranked.c.id, ranked.c.primary_post_id,
-                ranked.c.sha256, ranked.c.mime, ranked.c.total,
-            ).where(ranked.c.rn <= THUMBNAIL_LIMIT)
-        )).all()
+        stmt = select(
+            ranked.c.id, ranked.c.primary_post_id,
+            ranked.c.sha256, ranked.c.mime, ranked.c.total,
+        )
+        if limit is not None:
+            stmt = stmt.where(ranked.c.rn <= limit)
+        rows = (await self.session.execute(stmt)).all()
 
         out: dict[int, dict] = {pid: {"thumbs": [], "more": 0} for pid in post_ids}
         for img_id, pid, sha, mime, total in rows: