Using the same hostnames at home and over Tailscale

In my previous post about my terminal-native setup for coding agents, I described using Heeler to connect from my iPhone to Herdr running on my Mac. Heeler connects over SSH through Tailscale, but that setup left me with one small annoyance: the hostname depended on where I was.
At home, with Tailscale disabled, Bonjour made the Mac available as:
cookiebook.local Away from home, with Tailscale enabled, I used its Tailscale hostname instead.