Fix group preview bot admission and improve CI diagnostics

game/bots.ts

@@ -3229,7 +3229,8 @@ function policyActions(g: GameView): Action[] {
       if (card) return [{ type: 'card', card: card.id }];
     }
     if (g.nexus && !g.spiceWindow && !g.ready.includes(me.id) &&
-        (group?.variant === 'unlimited' || group?.variant === 'three-short') &&
+        (group?.variant === 'unlimited' || group?.variant === 'three-short' ||
+          !!group && g.coalitionPreview === 'three') &&
         !group.groups.some(alliance => alliance.members.includes(me.id))) {
       const limit = group.variant === 'unlimited' ? 6 : 3;
       const alliance = group.groups.find(candidate => candidate.members.length >= 2 && candidate.members.length < limit &&