The system keyboard is pushing up the nav bar, which in some uses is covering the input field. Annoying.

Hide the nav bar when the system keyboard is up. We never want to see this above the keyboard while the user is inputting a number.

AI desc:

The bottom tab bar is position:fixed to the visual viewport, so the
system keyboard pushed it up over the focused field. Hide the footer (and drop
fixed CTAs to bottom: 0) when a system-keyboard input is focused on mobile, or
when the visual viewport shrinks by a keyboard-sized inset. Custom amount
keypad fields stay unchanged so the in-app keypad still docks above the nav.

• cd cashtab && npm test -- --watchAll=false src/components/Common/__tests__/cashtabOsKeyboard.test.ts src/hooks/__tests__/useOsKeyboardChrome.test.ts src/components/Common/__tests__/cashtabAmountKeypadScroll.test.ts
• On a phone, focus a recipient/address or other system-keyboard field: bottom nav hides; dismiss the keyboard and the nav returns
• On Send, focus an amount field (custom keypad): keypad still docks above the nav
• Desktop sidebar nav is unchanged