feat: Add support for search_conversations in copilot (#11520)

Earlier, we were manually checking if a user was an agent and filtering
their conversations based on inboxes. This logic should have been part
of the conversation permissions service.

This PR moves the check to the right place and updates the logic
accordingly.

Other updates:
- Add support for search_conversations service for copilot.
- Use PermissionFilterService in contacts/conversations, conversations,
copilot search_conversations.

---------

Co-authored-by: Sojan <sojan@pepalo.com>
Co-authored-by: Sivin Varghese <64252451+iamsivin@users.noreply.github.com>
Co-authored-by: Muhsin Keloth <muhsinkeramam@gmail.com>

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

@@ -0,0 +1,67 @@
+require 'rails_helper'
+
+RSpec.describe Captain::Tools::Copilot::SearchConversationsService do
+  let(:account) { create(:account) }
+  let(:user) { create(:user, role: 'administrator', account: account) }
+  let(:assistant) { create(:captain_assistant, account: account) }
+  let(:service) { described_class.new(assistant, user: user) }
+
+  describe '#name' do
+    it 'returns the correct service name' do
+      expect(service.name).to eq('search_conversations')
+    end
+  end
+
+  describe '#description' do
+    it 'returns the service description' do
+      expect(service.description).to eq('Search conversations based on parameters')
+    end
+  end
+
+  describe '#parameters' do
+    it 'returns the correct parameter schema' do
+      params = service.parameters
+      expect(params[:type]).to eq('object')
+      expect(params[:properties]).to include(:contact_id, :status, :priority)
+    end
+  end
+
+  describe '#execute' do
+    let(:contact) { create(:contact, account: account) }
+    let!(:open_conversation) { create(:conversation, account: account, contact: contact, status: 'open', priority: 'high') }
+    let!(:resolved_conversation) { create(:conversation, account: account, status: 'resolved', priority: 'low') }
+
+    it 'returns all conversations when no filters are applied' do
+      result = service.execute({})
+      expect(result).to include('Total number of conversations: 2')
+      expect(result).to include(open_conversation.to_llm_text(include_contact_details: true))
+      expect(result).to include(resolved_conversation.to_llm_text(include_contact_details: true))
+    end
+
+    it 'filters conversations by status' do
+      result = service.execute({ 'status' => 'open' })
+      expect(result).to include('Total number of conversations: 1')
+      expect(result).to include(open_conversation.to_llm_text(include_contact_details: true))
+      expect(result).not_to include(resolved_conversation.to_llm_text(include_contact_details: true))
+    end
+
+    it 'filters conversations by contact_id' do
+      result = service.execute({ 'contact_id' => contact.id })
+      expect(result).to include('Total number of conversations: 1')
+      expect(result).to include(open_conversation.to_llm_text(include_contact_details: true))
+      expect(result).not_to include(resolved_conversation.to_llm_text(include_contact_details: true))
+    end
+
+    it 'filters conversations by priority' do
+      result = service.execute({ 'priority' => 'high' })
+      expect(result).to include('Total number of conversations: 1')
+      expect(result).to include(open_conversation.to_llm_text(include_contact_details: true))
+      expect(result).not_to include(resolved_conversation.to_llm_text(include_contact_details: true))
+    end
+
+    it 'returns appropriate message when no conversations are found' do
+      result = service.execute({ 'status' => 'snoozed' })
+      expect(result).to eq('No conversations found')
+    end
+  end
+end