Login and register each carried their own copy of the promo panel and the
error banner, so the two pages drifted apart and every caller had to wire
role="alert" by hand. Extract a shared AuthPromoCard and AuthAlert, use them
in both forms and for the login notices, and link errors to their fields via
aria-invalid / aria-describedby.
Focus now lands on the 2FA code field the moment it appears, the credential
fields lock while a request is in flight, and invalid inputs get a danger
tint. The homepage top bar was a byte-for-byte duplicate of AuthTopBar; it
now renders the shared component, and the compact homepage login uses the
tighter spacing its comment already promised.
