fix(auth): cap insurerIkNumber length before the digit refine

The insurerIkNumber field went straight to the 9-digit regex refine with
no upper bound, unlike its siblings insurerName and fullName which cap at
120 characters. Add a defensive .max(32) before the transform — well
above the 9 digits the value ever holds — so an oversized string is
rejected at the length gate rather than reaching the regex. The refine
already rejects malformed input; this is hardening for consistency with
the surrounding fields.

src/lib/validations/auth.ts

@@ -65,6 +65,7 @@ export const profileSchema = z.object({
   // the iOS client contract). Surfaced on the FHIR `Coverage` payor.
   insurerIkNumber: z
     .string()
+    .max(32)
     .nullable()
     .optional()
     .transform((v) => {