feat: Bulk delete for contacts (#12778)

Introduces a new bulk action `delete` for contacts

ref: https://github.com/chatwoot/chatwoot/pull/12763

## Screens

<img width="1492" height="973" alt="Screenshot 2025-10-31 at 6 27 21 PM"
src="https://github.com/user-attachments/assets/30dab1bb-2c2c-4168-9800-44e0eb5f8e3a"
/>
<img width="1492" height="985" alt="Screenshot 2025-10-31 at 6 27 32 PM"
src="https://github.com/user-attachments/assets/5be610c4-b19e-4614-a164-103b22337382"
/>

spec/services/contacts/bulk_delete_service_spec.rb

@@ -0,0 +1,24 @@
+require 'rails_helper'
+
+RSpec.describe Contacts::BulkDeleteService do
+  subject(:service) { described_class.new(account: account, contact_ids: contact_ids) }
+
+  let(:account) { create(:account) }
+  let!(:contact_one) { create(:contact, account: account) }
+  let!(:contact_two) { create(:contact, account: account) }
+  let(:contact_ids) { [contact_one.id, contact_two.id] }
+
+  describe '#perform' do
+    it 'deletes the provided contacts' do
+      expect { service.perform }
+        .to change { account.contacts.exists?(contact_one.id) }.from(true).to(false)
+        .and change { account.contacts.exists?(contact_two.id) }.from(true).to(false)
+    end
+
+    it 'returns when no contact ids are provided' do
+      empty_service = described_class.new(account: account, contact_ids: [])
+
+      expect { empty_service.perform }.not_to change(Contact, :count)
+    end
+  end
+end