Address PR feedback: error handling and test coverage

- Handle Stripe::InvalidRequestError in sync_customer_email_to_stripe
  (mirrors cancel method behavior for deleted customers)
- Add test for deactivated owner (owner with nil identity)
- Add test for deleted Stripe customer scenario

Author: jeremy

saas/app/models/account/subscription.rb

@@ -52,6 +52,9 @@ def sync_customer_email_to_stripe
     if stripe_customer_id && (email = owner_email)
       Stripe::Customer.update(stripe_customer_id, email: email)
     end
+  rescue Stripe::InvalidRequestError => e
+    # Customer already deleted in Stripe - treat as success
+    Rails.logger.warn "Stripe customer #{stripe_customer_id} not found during email sync: #{e.message}"
   end
 
   private

saas/test/models/account/subscription_test.rb

@@ -158,4 +158,37 @@ class Account::SubscriptionTest < ActiveSupport::TestCase
 
     subscription.sync_customer_email_to_stripe
   end
+
+  test "sync_customer_email_to_stripe does nothing when owner has no identity" do
+    account = accounts(:"37s")
+    owner = account.users.find_by(role: :owner) || account.users.first.tap { |u| u.update!(role: :owner) }
+    owner.update_column(:identity_id, nil)
+    subscription = account.create_subscription!(
+      stripe_customer_id: "cus_test",
+      plan_key: "monthly_v1",
+      status: "active"
+    )
+
+    Stripe::Customer.expects(:update).never
+
+    subscription.sync_customer_email_to_stripe
+  end
+
+  test "sync_customer_email_to_stripe treats deleted customer as success" do
+    account = accounts(:"37s")
+    account.users.find_by(role: :owner) || account.users.first.tap { |u| u.update!(role: :owner) }
+    subscription = account.create_subscription!(
+      stripe_customer_id: "cus_deleted",
+      plan_key: "monthly_v1",
+      status: "active"
+    )
+
+    Stripe::Customer.stubs(:update).raises(
+      Stripe::InvalidRequestError.new("No such customer", {})
+    )
+
+    assert_nothing_raised do
+      subscription.sync_customer_email_to_stripe
+    end
+  end
 end