Hide unfinished games from production builds

A release listed all eleven games with nine of them marked "Coming
soon", so most of the menu was a dead end for anyone installing from the
production channel. Production now lists only what can be played; dev
builds still show everything, which is where seeing the roadmap is
useful.

The menu reads the installed APK's own version name, so this follows the
build rather than the update channel selected for the future — a dev
build shows the full list even if its owner has switched back to
production for updates.

CatalogTest pins both views, including that filtering never empties a
category and strands its heading.

Co-Authored-By: Claude Opus 5 <[email protected]>
Claude-Session: https://claude.ai/code/session_015qjfMiPUDshdKEUa6vxqzN

README.md

@@ -12,7 +12,11 @@ The app shell is complete and two games are playable end to end:
 | **Playable** | Euchre, Sequence |
 | **Listed, not yet implemented** | Kaiser, President, Golf, Wizard, Crazy 8s, Mastermind, Backgammon, Chess, Checkers |
 
-Unimplemented games appear in the menu marked *Coming soon*. Adding one means
+Unimplemented games appear in the menu marked *Coming soon* **on dev builds
+only** — a production release lists just the games that can actually be played,
+so nobody installs it and taps into a dead end. The menu decides this from the
+installed APK's own version name, so it follows the build rather than the
+channel selected for future updates. Adding one means
 writing a `GameRules` implementation, a `GameAi`, and a screen, then flipping
 `available` in `GameCatalog` — the menu, lobby, networking, settings and OTA
 layers are game-agnostic and need no changes.