feat: Add manual WhatsApp templates sync with UI (#12007)

Fixes https://github.com/chatwoot/chatwoot/issues/9600

**Summary**
- Added manual WhatsApp templates sync functionality accessible via UI
- Added refresh button in both inbox settings and template picker modal
- Enhanced template picker to always show for WhatsApp Cloud channels
(even when empty)


**Preview**

<img width="1456" height="798" alt="CleanShot 2025-07-22 at 14 15 28@2x"
src="https://github.com/user-attachments/assets/8a04ff26-61fa-42ee-a1b8-5e06433ae6e0"
/>


<img width="2376" height="1574" alt="CleanShot 2025-07-22 at 14 19
24@2x"
src="https://github.com/user-attachments/assets/1c772034-04ff-484d-88dd-ca8123e93065"
/>

---------

Co-authored-by: iamsivin <iamsivin@gmail.com>

app/controllers/api/v1/accounts/inboxes_controller.rb

@@ -69,6 +69,17 @@ class Api::V1::Accounts::InboxesController < Api::V1::Accounts::BaseController
     render status: :ok, json: { message: I18n.t('messages.inbox_deletetion_response') }
   end
 
+  def sync_templates
+    unless @inbox.channel.is_a?(Channel::Whatsapp)
+      return render status: :unprocessable_entity, json: { error: 'Template sync is only available for WhatsApp channels' }
+    end
+
+    Channels::Whatsapp::TemplatesSyncJob.perform_later(@inbox.channel)
+    render status: :ok, json: { message: 'Template sync initiated successfully' }
+  rescue StandardError => e
+    render status: :internal_server_error, json: { error: e.message }
+  end
+
   private
 
   def fetch_inbox