fix(pwa): lift toasts above the bottom bar wherever the phone shell shows it

The toaster's mobile offset applies below 600 px only, while the bottom
bar follows the shell up to md and on a touch screen held sideways. In
between, the update toast and its reload button sat over the tabs.

src/components/providers.tsx

@@ -392,8 +392,9 @@ function OfflineMutationToaster() {
  * Below 600 px Sonner lays toasts across the bottom edge, 16 px up, which on
  * a phone is on top of the bottom bar: the "new version" hint sat over the
  * tabs and the add button until it was dismissed. The mobile offset lifts
- * them above the bar and the home indicator. From `md` the bar is gone and
- * the desktop offset applies.
+ * them above the bar and the home indicator. Sonner applies it below 600 px
+ * only, while the bar follows the shell (up to `md`, and a phone held
+ * sideways), so `globals.css` repeats the lift under `shell-mobile`.
  */
 function AppToaster() {
   const { resolvedTheme } = useTheme();