feat: captain should be able to access private notes (#11768)

# Pull Request Template

## Linear task: 

https://linear.app/chatwoot/issue/CW-4482/captain-should-be-able-to-access-private-notes-only-on-copilot

## Description

Captain should be able to access private notes (only on copilot)

## Type of change

- [x] New feature (non-breaking change which adds functionality)

## How Has This Been Tested?


![image](https://github.com/user-attachments/assets/b25cf81f-85eb-4adb-a1eb-57e1156b9b9e)


![image](https://github.com/user-attachments/assets/20051b31-cbce-41d9-84d9-13bc71687323)


## Checklist:

- [ ] My code follows the style guidelines of this project
- [ ] I have performed a self-review of my code
- [ ] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [ ] My changes generate no new warnings
- [ ] I have added tests that prove my fix is effective or that my
feature works
- [ ] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

spec/enterprise/services/captain/tools/copilot/get_conversation_service_spec.rb

@@ -128,6 +128,29 @@ RSpec.describe Captain::Tools::Copilot::GetConversationService do
         expect(result).to eq(conversation.to_llm_text)
       end
 
+      it 'includes private messages in the llm text format' do
+        # Create a regular message
+        create(:message,
+               conversation: conversation,
+               message_type: 'outgoing',
+               content: 'Regular message',
+               private: false)
+
+        # Create a private message
+        create(:message,
+               conversation: conversation,
+               message_type: 'outgoing',
+               content: 'Private note content',
+               private: true)
+
+        result = service.execute({ 'conversation_id' => conversation.display_id })
+
+        # Verify that the result includes both regular and private messages
+        expect(result).to include('Regular message')
+        expect(result).to include('Private note content')
+        expect(result).to include('[Private Note]')
+      end
+
       context 'when conversation belongs to different account' do
         let(:other_account) { create(:account) }
         let(:other_inbox) { create(:inbox, account: other_account) }