Fix mixed-deck Nexus Betrayal continuations

docs/NEXUS_HARKONNEN_RULES.md

@@ -2,6 +2,17 @@
 
 Source audit, 10 September 2026. This is a rules contract, not a runtime completion claim. The [common Nexus lifecycle](NEXUS_CARD_RULES.md) and existing expansion release gates still apply. The pending reaction-privacy question remains unresolved; this audit does not authorize a Betrayal reaction policy.
 
+## Basic selected decks — 30 October 2026
+
+Supported fresh selected-deck core games now retain the existing Harkonnen
+reaction for Basic native expansion leaders and the Ix Cheap Hero Traitor.
+Physical stock includes the selected decks and any Richese cache; older classic
+receipt signatures retain their prior format. The Ix phase-opening window can
+precede the mandatory Mentat replacement without losing the obligation. The
+existing provisional acknowledgement convention is unchanged. Advanced
+selected-deck reactions, uninitialized profiles, wider nested interactions and
+complete acceptance remain open. [Scope and evidence](NEXUS_CARD_RULES.md#basic-mixed-deck-nexus-reactions--30-october-2026).
+
 ## Earned phase cards and original replacement — 18 October 2026
 
 Fresh classic core now retains Tech3+ and Advanced Strongholds2+ with