Restore the Katan catalogue entry the engine depends on

The Option 2 migration dropped Gitea's 5c797c8, which added GameCatalog.CATAN
and a Katan entry (available = false: Coming soon on dev, hidden from
production). CatanRules.kt references GameCatalog.CATAN, so the merge did not
compile without it. Taken verbatim from feature/catan-engine, with the
matching CatalogTest assertions.

Co-Authored-By: Claude Sonnet 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01JdMNbY5hLR7FjtfEE712xG

app/src/test/java/org/prolibertate/games/game/CatalogTest.kt

@@ -106,17 +106,19 @@ class CatalogTest {
     }
 
     @Test
-    fun `every game in the catalogue can be played`() {
-        // There is nothing left marked "coming soon". The machinery that hides
-        // unfinished games from a production build is still there and still
-        // tested above — it simply has nothing to hide at the moment, and this
-        // is what will fail the day something is added to the list before its
-        // engine is written.
-        assertTrue(GameCatalog.all.all { it.available })
+    fun `every reference game in the catalogue can be played`() {
+        // Every game the app ships is playable. The one exception is Katan,
+        // listed so the slot exists and marked *Coming soon* until its engine
+        // and screen land — `available = false` is what keeps an unfinished
+        // game out of a production build while leaving it visible on a dev one.
         assertEquals(
-            GameCatalog.inMenu(GameMenu.BOARD, includeComingSoon = false),
-            GameCatalog.inMenu(GameMenu.BOARD, includeComingSoon = true),
+            listOf(GameCatalog.CATAN),
+            GameCatalog.all.filterNot { it.available }.map { it.id },
         )
+        // It is also the only difference the two channels see in a menu.
+        val hiddenFromProduction = GameCatalog.inMenu(GameMenu.BOARD, includeComingSoon = true) -
+            GameCatalog.inMenu(GameMenu.BOARD, includeComingSoon = false)
+        assertEquals(listOf(GameCatalog.byId(GameCatalog.CATAN)!!), hiddenFromProduction)
     }
 
     @Test