GitHub OAuth button disablement

code.js

// By default the oauth button remains disabled until the visitor focusses the
// window. This event handler enables the button once the window has been focussed.
async function updateButtonOnPageFocused(button: Element) {
  await pageFocused(document)
  await new Promise(resolve => setTimeout(resolve, 1000))
  if (button instanceof HTMLButtonElement) button.disabled = false
}