- BackupReminder: wait while the signup dialog is open (the key is minted
mid-flow), so "Save your login" no longer pops before signup is finished.
Uses a small non-reactive signup flag set by SignupDialog.
- BackupReminder: removed the custom close button — the Sheet already renders
its own X (the sheet's close now snoozes for the session).
- CreateEventPage: the "Link to a Skate Spot" row no longer overlaps — the
label/hint can shrink and the Select Spot button stays put.
