fix: restore popupOverlayStyle import in ExternalMyInvoices

Removed during popup refactor but still used by +Invoice form popup.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

.claude/settings.local.json

@@ -14,7 +14,8 @@
       "Bash(git push *)",
       "Bash(vercel --prod --yes)",
       "Bash(sed -n '1,15p' src/pages/external/ExternalMyInvoices.jsx)",
-      "Bash(sed -n '1,15p' src/pages/client/ClientMyInvoices.jsx)"
+      "Bash(sed -n '1,15p' src/pages/client/ClientMyInvoices.jsx)",
+      "Bash(git commit -q -m 'fix: restore popupOverlayStyle import in ExternalMyInvoices *)"
     ]
   }
 }

src/pages/external/ExternalMyInvoices.jsx

@@ -9,6 +9,7 @@ import { readPageCache, writePageCache } from '../../lib/pageCache';
 import { useSortable } from '../../hooks/useSortable';
 import { isCompletedVersionEligible } from '../../lib/invoiceVersionRules';
 import SubcontractorInvoiceForm from '../../components/SubcontractorInvoiceForm';
+import { popupOverlayStyle, popupSurfaceStyle } from '../../lib/popupStyles';
 import InvoiceDetailPopup, { POPUP_FIELD_LABEL } from '../../components/InvoiceDetailPopup';
 import InvoicePopupTable from '../../components/InvoicePopupTable';
 import { generateSubcontractorPOPDF } from '../../lib/invoice';