Adds viewportFit: 'cover' so the PWA can draw under the notch /
Dynamic Island when installed. Nav and Toast read env(safe-area-inset-*)
to keep their content out of the hardware cutouts (no-op on browsers
without a notch — env() resolves to 0).
Replaces autoFocus on the first field of CreateAccountDialog and
CreateUserDialog with a useEffect that only focuses on pointer devices
(matchMedia '(hover: hover) and (pointer: fine)'). Phones no longer
get the soft keyboard popping the instant a dialog opens.
Adds a small top-centered <Toast> that fires only when the Server
Action returns { ok: true } (i.e., the DB write actually succeeded).
Auto-dismisses after 3s.
Wires both create dialogs (CreateAccountDialog, CreateUserDialog) with
an onSuccess callback that the table parent uses to push the toast,
and the delete confirm-flow does the same. Inline-edit success stays
quiet (no toast) — only add/delete trigger it, per the requested
scope.
