feat(games): add coming badge for unreleased games

README.md

@@ -25,6 +25,9 @@ To Be Played is split into three repositories:
   days ("this month: +N added, -N off the pile") and a random suggestion,
   Steam avatar and a banner from the most played game of the last two weeks, and an achievement card: unlocked
   total, perfect games, average completion and the 5 games closest to 100 %.
+- **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`): three backlog picks for a time budget (up to 5 / 15 / 40 h or any) and a mood
   (story, co-op, chill, action, scary from IGDB; speedrun from speedrun.com). Each pick says why: like a game you
   played a lot, waiting longest, or random. Reroll without repeats, and "Start playing" in one click.