The bank form posted {id, bank:{...}} (nested) but the route/schema read fields
at the top level; lenient z.object silently stripped the wrapper, so every field
saved as null while returning success. Flatten the payload to top level and switch
the create/update schemas to strictObject so a future nesting 400s loudly instead
of saving a blank record. Affects both create and edit.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
