Allow Ecaz Ambassadors on the placed mobile stronghold

Share dynamic stronghold legality across placement, cancellation, bots and controls. Keep the HMS sheltered, preserve original fees and entry effects, and display its public Ambassador attached to the stronghold interior.

Cover genuine Basic/Advanced placement, paid movement entry, card continuations, prevention and native relocation. No Terror or direct-shipment permission is added.

docs/RULE_DECISIONS.md

@@ -1,5 +1,15 @@
 # Rule decision index
 
+## Ecaz Ambassador on the placed HMS — 24 October 2026
+
+Compose E3 any-stronghold placement (p7; authorized revised p30,A) with E1
+p9 HMS identity and intrinsic storm shelter. The token attaches to the HMS
+interior, retaining original fees, trigger exclusions and native relocation;
+no other faction gains direct shipment. E3 expressly excludes Terror instead.
+No direct HMS/Ambassador clarification was found in the bounded official
+search; this is general source composition, without a new priority or numerical
+ruling. [Source, permission and boundaries](ECAZ_AMBASSADORS_RULES.md#placed-hidden-mobile-stronghold--24-october-2026).
+
 ## Provisional Basic Guild Ambassador No-Field composition — 24 October 2026
 
 Use the 14 October choose-recommended authority for the previously gated