Block scripts and triggers: data model, Rhai translation and runtime

Editor missions keep a painted map or roll a random map per campaign run,
leave out goals they cannot have, and run their triggers in the fixed step.

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

lang/de.lang

@@ -882,6 +882,8 @@ msg.tool_research = Noch nicht erforscht - Kreaturen in der Bibliothek arbeiten
 msg.script = {0}
 msg.script_objective = Ziel: {0}
 msg.script_error = Skriptfehler: {0}
+msg.script_hint = Krummfinger: {0}
+msg.mission_start_custom = Mission: {0}
 msg.script_language = Unbekannte Missionssprache: {0}
 
 # spells