feat: block replies during agent bot ownership

spec/controllers/api/v1/accounts/conversations/messages_controller_spec.rb

@@ -36,6 +36,33 @@ RSpec.describe 'Conversation Messages API', type: :request do
         expect(conversation.messages.first.content).to eq(params[:content])
       end
 
+      it 'blocks public replies when an agent bot owns the conversation' do
+        conversation.update!(assignee_agent_bot: create(:agent_bot, account: account))
+        params = { content: 'test-message', private: false }
+
+        post api_v1_account_conversation_messages_url(account_id: account.id, conversation_id: conversation.display_id),
+             params: params,
+             headers: agent.create_new_auth_token,
+             as: :json
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(response.parsed_body['error']).to eq('Conversation is assigned to an Agent Bot. Take over the conversation before replying.')
+        expect(conversation.messages.count).to eq(0)
+      end
+
+      it 'allows private notes when an agent bot owns the conversation' do
+        conversation.update!(assignee_agent_bot: create(:agent_bot, account: account))
+        params = { content: 'test-note', private: true }
+
+        post api_v1_account_conversation_messages_url(account_id: account.id, conversation_id: conversation.display_id),
+             params: params,
+             headers: agent.create_new_auth_token,
+             as: :json
+
+        expect(response).to have_http_status(:success)
+        expect(conversation.messages.last).to be_private
+      end
+
       it 'does not create the message' do
         params = { content: "#{'h' * 150 * 1000}a", private: true }