chore: Automate SSL with Cloudflare (#12021)

This PR adds support for automatic SSL issuance using Cloudflare when a
custom domain is updated.

- Introduced a cloudflare configuration. If present, the system will
attempt to issue an SSL certificate via Cloudflare whenever a custom
domain is added or changed.
- SSL verification is handled using an HTTP challenge.
- The job will store the HTTP challenge response provided by Cloudflare
and serve it under the /.well-known/cf path automatically.

How to test:

- Create a Cloudflare zone for your domain and copy the Zone ID.
- Generate a Cloudflare API token with the required SSL certificate
permissions.
- Set the Fallback Origin under SSL -> Custom HostName to the Chatwoot
installation.
- Add or update a custom domain and verify that the SSL certificate is
automatically issued.

---------

Co-authored-by: Sojan Jose <sojan@pepalo.com>

spec/enterprise/models/enterprise/concerns/portal_spec.rb

@@ -0,0 +1,59 @@
+require 'rails_helper'
+
+RSpec.describe Enterprise::Concerns::Portal do
+  describe '#enqueue_cloudflare_verification' do
+    let(:portal) { create(:portal, custom_domain: nil) }
+
+    context 'when custom_domain is changed' do
+      context 'when on chatwoot cloud' do
+        before do
+          allow(ChatwootApp).to receive(:chatwoot_cloud?).and_return(true)
+        end
+
+        it 'enqueues cloudflare verification job' do
+          expect do
+            portal.update(custom_domain: 'test.example.com')
+          end.to have_enqueued_job(Enterprise::CloudflareVerificationJob).with(portal.id)
+        end
+      end
+
+      context 'when not on chatwoot cloud' do
+        before do
+          allow(ChatwootApp).to receive(:chatwoot_cloud?).and_return(false)
+        end
+
+        it 'does not enqueue cloudflare verification job' do
+          expect do
+            portal.update(custom_domain: 'test.example.com')
+          end.not_to have_enqueued_job(Enterprise::CloudflareVerificationJob)
+        end
+      end
+    end
+
+    context 'when custom_domain is not changed' do
+      before do
+        allow(ChatwootApp).to receive(:chatwoot_cloud?).and_return(true)
+        portal.update(custom_domain: 'test.example.com')
+      end
+
+      it 'does not enqueue cloudflare verification job' do
+        expect do
+          portal.update(name: 'New Name')
+        end.not_to have_enqueued_job(Enterprise::CloudflareVerificationJob)
+      end
+    end
+
+    context 'when custom_domain is set to blank' do
+      before do
+        allow(ChatwootApp).to receive(:chatwoot_cloud?).and_return(true)
+        portal.update(custom_domain: 'test.example.com')
+      end
+
+      it 'does not enqueue cloudflare verification job' do
+        expect do
+          portal.update(custom_domain: '')
+        end.not_to have_enqueued_job(Enterprise::CloudflareVerificationJob)
+      end
+    end
+  end
+end