feat: Allow customizing the responses, flows in Captain (#11385)

- Ability to provide custom instructions to captain

<img width="1107" alt="Screenshot 2025-04-28 at 6 11 43 PM"
src="https://github.com/user-attachments/assets/f94cbccc-b4d8-48fd-b6b9-55524129bc50"
/>

enterprise/app/jobs/captain/conversation/response_builder_job.rb

@@ -60,7 +60,7 @@ class Captain::Conversation::ResponseBuilderJob < ApplicationJob
   end
 
   def create_handoff_message
-    create_outgoing_message('Transferring to another agent for further assistance.')
+    create_outgoing_message(@assistant.config['handoff_message'] || 'Transferring to another agent for further assistance.')
   end
 
   def create_messages

enterprise/app/jobs/captain/inbox_pending_conversations_resolution_job.rb

@@ -5,12 +5,13 @@ class Captain::InboxPendingConversationsResolutionJob < ApplicationJob
     # limiting the number of conversations to be resolved to avoid any performance issues
     resolvable_conversations = inbox.conversations.pending.where('last_activity_at < ? ', Time.now.utc - 1.hour).limit(Limits::BULK_ACTIONS_LIMIT)
     resolvable_conversations.each do |conversation|
+      resolution_message = conversation.inbox.captain_assistant.config['resolution_message']
       conversation.messages.create!(
         {
           message_type: :outgoing,
           account_id: conversation.account_id,
           inbox_id: conversation.inbox_id,
-          content: I18n.t('conversations.activity.auto_resolution_message')
+          content: resolution_message || I18n.t('conversations.activity.auto_resolution_message')
         }
       )
       conversation.resolved!