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>

db/schema.rb

@@ -943,6 +943,7 @@ ActiveRecord::Schema[7.1].define(version: 2025_07_22_152516) do
     t.jsonb "config", default: {"allowed_locales" => ["en"]}
     t.boolean "archived", default: false
     t.bigint "channel_web_widget_id"
+    t.jsonb "ssl_settings", default: {}, null: false
     t.index ["channel_web_widget_id"], name: "index_portals_on_channel_web_widget_id"
     t.index ["custom_domain"], name: "index_portals_on_custom_domain", unique: true
     t.index ["slug"], name: "index_portals_on_slug", unique: true