Fix in-app reminder banner clipping behind bottom nav.

Position the banner above the nav using --bottom-nav-height instead of bottom-16.

components/reminders/in-app-reminder-banner.tsx

@@ -35,7 +35,8 @@ export function InAppReminderBanner() {
     <div
       role="status"
       aria-live="polite"
-      className="fixed inset-x-0 bottom-16 z-50 px-4"
+      className="fixed inset-x-0 z-[60] px-4 pb-[env(safe-area-inset-bottom,0px)]"
+      style={{ bottom: "calc(var(--bottom-nav-height) + 0.5rem)" }}
     >
       <div className="mx-auto flex max-w-lg items-start gap-3 rounded-xl border border-primary/30 bg-card p-4 shadow-lg">
         <div className="rounded-full bg-primary/10 p-2">