feat(cloud): Add support for viewing status of SSL in custom domains (#12011)

# Pull Request Template

## Description

Fixes
[CW-4620](https://linear.app/chatwoot/issue/CW-4620/rethinking-custom-domains-in-chatwoot)

<img width="642" height="187" alt="Screenshot 2025-07-29 at 8 17 44 PM"
src="https://github.com/user-attachments/assets/ad2f5dac-4b27-4dce-93ca-6cbba74443fb"
/>


## Type of change

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

## How Has This Been Tested?



## Checklist:

- [x] My code follows the style guidelines of this project
- [x] I have performed a self-review of my code
- [x] I have commented on my code, particularly in hard-to-understand
areas
- [ ] I have made corresponding changes to the documentation
- [x] My changes generate no new warnings
- [x] I have added tests that prove my fix is effective or that my
feature works
- [x] New and existing unit tests pass locally with my changes
- [ ] Any dependent changes have been merged and published in downstream
modules

---------

Co-authored-by: Vishnu Narayanan <iamwishnu@gmail.com>
Co-authored-by: Pranav <pranavrajs@gmail.com>
Co-authored-by: Pranav <pranav@chatwoot.com>

spec/controllers/api/v1/accounts/portals_controller_spec.rb

@@ -210,4 +210,76 @@ RSpec.describe 'Api::V1::Accounts::Portals', type: :request do
       end
     end
   end
+
+  describe 'POST /api/v1/accounts/{account.id}/portals/{portal.slug}/send_instructions' do
+    let(:portal_with_domain) { create(:portal, slug: 'portal-with-domain', account_id: account.id, custom_domain: 'docs.example.com') }
+
+    context 'when it is an unauthenticated user' do
+      it 'returns unauthorized' do
+        post "/api/v1/accounts/#{account.id}/portals/#{portal_with_domain.slug}/send_instructions",
+             params: { email: 'dev@example.com' }
+
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+
+    context 'when it is an authenticated agent' do
+      it 'returns unauthorized' do
+        post "/api/v1/accounts/#{account.id}/portals/#{portal_with_domain.slug}/send_instructions",
+             headers: agent.create_new_auth_token,
+             params: { email: 'dev@example.com' },
+             as: :json
+
+        expect(response).to have_http_status(:unauthorized)
+      end
+    end
+
+    context 'when it is an authenticated admin' do
+      it 'returns error when email is missing' do
+        post "/api/v1/accounts/#{account.id}/portals/#{portal_with_domain.slug}/send_instructions",
+             headers: admin.create_new_auth_token,
+             params: {},
+             as: :json
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(response.parsed_body['error']).to eq('Email is required')
+      end
+
+      it 'returns error when email is invalid' do
+        post "/api/v1/accounts/#{account.id}/portals/#{portal_with_domain.slug}/send_instructions",
+             headers: admin.create_new_auth_token,
+             params: { email: 'invalid-email' },
+             as: :json
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(response.parsed_body['error']).to eq('Invalid email format')
+      end
+
+      it 'returns error when custom domain is not configured' do
+        post "/api/v1/accounts/#{account.id}/portals/#{portal.slug}/send_instructions",
+             headers: admin.create_new_auth_token,
+             params: { email: 'dev@example.com' },
+             as: :json
+
+        expect(response).to have_http_status(:unprocessable_entity)
+        expect(response.parsed_body['error']).to eq('Custom domain is not configured')
+      end
+
+      it 'sends instructions successfully' do
+        mailer_double = instance_double(ActionMailer::MessageDelivery)
+        allow(PortalInstructionsMailer).to receive(:send_cname_instructions).and_return(mailer_double)
+        allow(mailer_double).to receive(:deliver_later)
+
+        post "/api/v1/accounts/#{account.id}/portals/#{portal_with_domain.slug}/send_instructions",
+             headers: admin.create_new_auth_token,
+             params: { email: 'dev@example.com' },
+             as: :json
+
+        expect(response).to have_http_status(:success)
+        expect(response.parsed_body['message']).to eq('Instructions sent successfully')
+        expect(PortalInstructionsMailer).to have_received(:send_cname_instructions)
+          .with(portal: portal_with_domain, recipient_email: 'dev@example.com')
+      end
+    end
+  end
 end