As the year winds down, it’s worth taking a bit of time to modernize the way you sign in to the accounts that matter most. Passkeys have been rolling out quietly across banks, tech platforms and everyday apps, and they solve a basic security problem passwords have had for decades. They can’t be guessed, phished or leaked in a breach because they never leave your device in the first place. Passkeys sound like one more tech term you’re supposed to pretend to understand, but...