AuthForm disables the switch-auth Link while submit is pending so pointer
click and Enter can no longer leave the auth route and lose the draft/error
context. The form restores a true Link after the request settles.
CardsPage/CardPage distinguish cold vs cached banking failures:
- cold card/section errors expose accessible alert + retry
- cached failures keep the previous data and offer a section GET retry
- summary-only/history-only outages do not hide successful sections
- notFound still skips the retry CTA
Tests cover the pending link guard, cold/cached cards error with retry,
summary failure with retry, and the prerequisite card list recovery.
Closes#56, #57
ksv741