Hero waves march on the strongest master

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/MULTIPLAYER.md

@@ -10,6 +10,8 @@ Multiplayer is only available for users of a server (not in the standalone file)
 - The match **pauses while a player is missing** (connection lost); a player who **leaves** is replaced by an AI.
 - Before the start, the host manually marks a free seat as AI with `{"t":"set_ai","side":n,"ai":true}` and clears it again with `ai:false`; side 0 stays human.
 - The humans (hero waves of the Order) as a third party (can be switched off), chat, alliances/teams.
+  Every wave marches on the strongest master still standing (creatures, towers, gold) – player or
+  AI rival – and is measured against him; the other players learn whom it attacks.
 - Coop is "separate but helpful": own heart, gold, mana, research and creatures; allies never fight each
   other, their creatures help each other, gold can be sent, allied ground can be walked; a fallen heart only
   knocks out that player (who may keep watching); the allies win when all enemies have fallen.