chore: Handle WebPush rate limiting in push notification service (#12184)

Implemented a rescue block for WebPush::TooManyRequests that logs
warnings during rate limiting events. This captures user email and
account ID for better traceability. We will implement a proper
throttling mechanism after identifying patterns across accounts.

app/services/notification/push_notification_service.rb

@@ -68,14 +68,23 @@ class Notification::PushNotificationService
 
     WebPush.payload_send(**browser_push_payload(subscription))
     Rails.logger.info("Browser push sent to #{user.email} with title #{push_message[:title]}")
-  rescue WebPush::ExpiredSubscription, WebPush::InvalidSubscription, WebPush::Unauthorized => e
-    Rails.logger.info "WebPush subscription expired: #{e.message}"
-    subscription.destroy!
-  rescue Errno::ECONNRESET, Net::OpenTimeout, Net::ReadTimeout => e
-    Rails.logger.error "WebPush operation error: #{e.message}"
   rescue StandardError => e
-    ChatwootExceptionTracker.new(e, account: notification.account).capture_exception
-    true
+    handle_browser_push_error(e, subscription)
+  end
+
+  def handle_browser_push_error(error, subscription)
+    case error
+    when WebPush::ExpiredSubscription, WebPush::InvalidSubscription, WebPush::Unauthorized
+      Rails.logger.info "WebPush subscription expired: #{error.message}"
+      subscription.destroy!
+    when WebPush::TooManyRequests
+      Rails.logger.warn "WebPush rate limited for #{user.email} on account #{notification.account.id}: #{error.message}"
+    when Errno::ECONNRESET, Net::OpenTimeout, Net::ReadTimeout
+      Rails.logger.error "WebPush operation error: #{error.message}"
+    else
+      ChatwootExceptionTracker.new(error, account: notification.account).capture_exception
+      true
+    end
   end
 
   def send_fcm_push(subscription)