feat(play-next): add series and studio rows

README.md

@@ -28,8 +28,9 @@ To Be Played is split into three repositories:
 - **Coming games**: a game that is not released yet (and nobody played) shows a "Coming <date>" badge in the library, on
   the details page, in the stat game lists and on the public profile. The pile counts only the games Core sends in
   `pileGames`, so coming games are not on it; Core never picks them.
-- **What to play next** (`/play-next`): four rows of up to 3 backlog games each: up next (your own backlog order),
-  because you played (a similar game for each of your 3 most played), longest on your list, and mood picks. A time
+- **What to play next** (`/play-next`): six rows of up to 3 backlog games each: up next (your own backlog order),
+  next in series (the next part of a series you played), because you played (a similar game for each of your 3 most
+  played), same studio (a developer you played), longest on your list, and mood picks. A time
   budget (up to 5 / 15 / 40 h or any) filters all rows; a mood (story, co-op, chill, action, scary from IGDB; speedrun
   from speedrun.com) only the mood row. Each row has its own reroll without repeats, and "Start playing" in one click.
   On a phone each row scrolls sideways.