feat: add per-inbox toggle to disable incoming calls (#14645)

## Description

Adds a per-inbox "Allow incoming calls" toggle for voice-enabled
WhatsApp and Twilio inboxes. When turned off, the setting is persisted
on the channel; actually rejecting inbound calls is handled in a
follow-up PR.

## Type of change

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

## Screenshot
<img width="804" height="384" alt="Screenshot 2026-06-04 at 11 44 07 AM"
src="https://github.com/user-attachments/assets/df8bb026-0387-4031-bcba-6d9a56872eb7"
/>


## 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

spec/enterprise/controllers/enterprise/api/v1/accounts/inboxes_controller_spec.rb

@@ -49,6 +49,59 @@ RSpec.describe 'Enterprise Inboxes API', type: :request do
     end
   end
 
+  describe 'POST /api/v1/accounts/{account.id}/inboxes/:id/set_inbound_calls' do
+    before do
+      allow(Twilio::VoiceWebhookSetupService).to receive(:new)
+        .and_return(instance_double(Twilio::VoiceWebhookSetupService, perform: "AP#{SecureRandom.hex(16)}"))
+    end
+
+    context 'when administrator' do
+      it 'disables inbound calls on a Twilio voice inbox' do
+        channel = create(:channel_twilio_sms, :with_voice, account: account)
+
+        post "/api/v1/accounts/#{account.id}/inboxes/#{channel.inbox.id}/set_inbound_calls",
+             headers: admin.create_new_auth_token,
+             params: { inbound_calls_enabled: false },
+             as: :json
+
+        expect(response).to have_http_status(:ok)
+        expect(channel.reload.inbound_calls_enabled?).to be false
+      end
+
+      it 'enables inbound calls on a WhatsApp inbox without re-validating provider config' do
+        account.enable_features('channel_voice')
+        account.save!
+        channel = create(:channel_whatsapp, account: account, provider: 'whatsapp_cloud',
+                                            validate_provider_config: false, sync_templates: false)
+        channel.update!(provider_config: channel.provider_config.merge('calling_enabled' => true, 'inbound_calls_enabled' => false))
+
+        post "/api/v1/accounts/#{account.id}/inboxes/#{channel.inbox.id}/set_inbound_calls",
+             headers: admin.create_new_auth_token,
+             params: { inbound_calls_enabled: true },
+             as: :json
+
+        expect(response).to have_http_status(:ok)
+        expect(channel.reload.inbound_calls_enabled?).to be true
+      end
+    end
+
+    context 'when agent' do
+      let(:agent) { create(:user, account: account, role: :agent) }
+
+      it 'is forbidden' do
+        channel = create(:channel_twilio_sms, :with_voice, account: account)
+
+        post "/api/v1/accounts/#{account.id}/inboxes/#{channel.inbox.id}/set_inbound_calls",
+             headers: agent.create_new_auth_token,
+             params: { inbound_calls_enabled: false },
+             as: :json
+
+        expect(response).to have_http_status(:unauthorized)
+        expect(channel.reload.inbound_calls_enabled?).to be true
+      end
+    end
+  end
+
   describe 'PATCH /api/v1/accounts/{account.id}/inboxes/:id' do
     let(:inbox) { create(:inbox, account: account, auto_assignment_config: { max_assignment_limit: 5 }) }
 

spec/enterprise/controllers/twilio/voice_controller_spec.rb

@@ -112,6 +112,23 @@ RSpec.describe 'Twilio::VoiceController', type: :request do
       }
       expect(response).to have_http_status(:not_found)
     end
+
+    it 'rejects the inbound contact leg without building a call when inbound calls are disabled' do
+      channel.update!(provider_config: { 'inbound_calls_enabled' => false })
+      expect(Voice::InboundCallBuilder).not_to receive(:perform!)
+
+      expect do
+        post "/twilio/voice/call/#{digits}", params: {
+          'CallSid' => call_sid,
+          'From' => from_number,
+          'To' => to_number,
+          'Direction' => 'inbound'
+        }
+      end.not_to change(Call, :count)
+
+      expect(response).to have_http_status(:ok)
+      expect(response.body).to include('<Reject')
+    end
   end
 
   describe 'POST /twilio/voice/status/:phone' do