fix: CCA preauth status stays Submitted (not Approved) and screenshot mime type

- ccaPreAuthProcessor: keep claim status as PREAUTH after successful
  submission instead of jumping straight to APPROVED, matching the
  Tufts SCO/UnitedDH/MassHealth preauth flows; also tag PNG fallback
  screenshots with image/png instead of the default application/pdf
  so they render in the Documents preview modal.
- claims-recent-table: add a PREAUTH status case so it displays as
  "Submitted" instead of falling through to the raw enum value.

apps/Frontend/src/components/claims/claims-recent-table.tsx

@@ -287,6 +287,12 @@ export default function ClaimsRecentTable({
           color: "bg-red-100 text-red-800",
           icon: <AlertCircle className="h-3 w-3 mr-1" />,
         };
+      case "PREAUTH":
+        return {
+          label: "Submitted",
+          color: "bg-blue-100 text-blue-800",
+          icon: <Clock className="h-3 w-3 mr-1" />,
+        };
       default:
         return {
           label: status