feat: Add support for multi-language support for Captain (#11068)

This PR implements the following features

- FAQs from conversations will be generated in account language
- Contact notes will be generated in account language
- Copilot chat will respond in user language, unless the agent asks the
question in a different language

## Changes
### Copilot Chat

- Update the prompt to include an instruction for the language, the bot
will reply in asked language, but will default to account language
- Update the `ChatService` class to include pass the language to
`SystemPromptsService`

### FAQ and Contact note generation

- Update contact note generator and conversation generator to include
account locale
- Pass the account locale to `SystemPromptsService`


<details><summary>Screenshots</summary>

#### FAQs being generated in system langauge

![CleanShot 2025-03-12 at 13 32
30@2x](https://github.com/user-attachments/assets/84685bd8-3785-4432-aff3-419f60d96dd3)


#### Copilot responding in system language

![CleanShot 2025-03-12 at 13 47
03@2x](https://github.com/user-attachments/assets/38383293-4228-47bd-b74a-773e9a194f90)


</details>

---------

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

spec/enterprise/services/captain/llm/conversation_faq_service_spec.rb

@@ -145,5 +145,25 @@ RSpec.describe Captain::Llm::ConversationFaqService do
         { role: 'user', content: conversation.to_llm_text }
       )
     end
+
+    context 'when conversation has different language' do
+      let(:account) { create(:account, locale: 'fr') }
+      let(:conversation) do
+        create(:conversation, account: account,
+                              first_reply_created_at: Time.zone.now)
+      end
+
+      it 'includes system prompt with correct language' do
+        allow(Captain::Llm::SystemPromptsService).to receive(:conversation_faq_generator)
+          .with('french')
+          .and_return('system prompt in french')
+
+        params = service.send(:chat_parameters)
+
+        expect(params[:messages]).to include(
+          { role: 'system', content: 'system prompt in french' }
+        )
+      end
+    end
   end
 end