refactor(captain): simplify audience param permitting and engagement check

Drops the unreachable permitted[:config] fallback in the assistants
controller and the redundant respond_to? guard in the hook execution
service's captain_should_engage?.

enterprise/app/controllers/api/v1/accounts/captain/assistants_controller.rb

@@ -112,19 +112,18 @@ class Api::V1::Accounts::Captain::AssistantsController < Api::V1::Accounts::Base
 
     permitted[:guardrails] = params[:assistant][:guardrails] if params[:assistant].key?(:guardrails)
 
-    # The audience is a recursive condition tree that strong params can't whitelist by shape;
-    # route it through separately. Validity is enforced by Captain::AudienceValidator.
     permit_audience_config(permitted)
 
     permitted
   end
 
+  # The audience is a recursive condition tree that strong params can't whitelist by shape;
+  # pass it through raw and let Captain::AudienceValidator enforce validity.
   def permit_audience_config(permitted)
     config = params[:assistant][:config]
-    return unless config.respond_to?(:key?) && config.key?(:audience)
+    return unless config.try(:key?, :audience)
 
     audience = config[:audience]
-    permitted[:config] ||= ActionController::Parameters.new.permit!
     permitted[:config][:audience] = audience.respond_to?(:permit!) ? audience.permit!.to_h : audience
   end
 

enterprise/app/services/enterprise/message_templates/hook_execution_service.rb

@@ -79,12 +79,8 @@ module Enterprise::MessageTemplates::HookExecutionService
     conversation.pending? && captain_should_engage?
   end
 
-  # True only when the inbox has a Captain assistant that should engage this conversation now —
-  # i.e. the contact is within the audience AND the assistant is on-schedule. Otherwise the
-  # conversation falls back to normal human handling (greeting/OOO templates fire, Captain silent).
   def captain_should_engage?
-    inbox.respond_to?(:captain_assistant) &&
-      inbox.captain_assistant.present? &&
-      inbox.captain_assistant.engages?(conversation.contact, conversation)
+    assistant = inbox.captain_assistant
+    assistant.present? && assistant.engages?(conversation.contact, conversation)
   end
 end