Unify form styling across invoice, estimate, and recurring invoice pages

Apply consistent rounded-xl shadow border-line-light to customer
selector, date/number fields card, items table, totals card, editor,
tax popup, and view page sidebars. Wrap right-side basic fields in
card container matching the customer card.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

resources/scripts/admin/views/recurring-invoices/create/RecurringInvoiceCreateBasicFields.vue

@@ -36,6 +36,7 @@
       gap-4
       mt-8
       lg:gap-6 lg:mt-0 lg:grid-cols-2
+      rounded-xl shadow border border-line-light bg-surface p-5
     "
   >
     <BaseInputGroup