Replace raw Dialog/AlertDialog scaffolding in MfaEnrollDialog,
MfaDisableDialog, and MfaBackupCodesDialog with the shared Modal*
primitives introduced in D-1. Extract the duplicated BackupCodeTicket
component into a shared file consumed by both enroll and regen flows.
Fix a CSS grid auto-column blowout in Modal: the dialog's implicit auto
column was sizing to the step rail's min-content (492px), overflowing
the 448px max-w-md constraint and clipping right-side content. Adding
grid-cols-1 to the DialogContent override forces the column to use
minmax(0, 1fr), preventing any grid item from expanding the track past
available space. Also add min-w-0 to the TOTP secret code element so
its long monospaced string can truncate rather than drive column sizing.
Kicker prefixes updated to SECURITY · per the tracker convention.
Anso