Created directory says teammates find it, but a Mac on another directory never does #603

"Your team's directory is running" tells the creator that teammates' Macs find it by themselves, but a Mac that already has a directory never switches to it, even when that directory is failing.

What was seen

• B created a directory served by nate16-1. The dialog said "Teammates' Macs find it on the tailnet. There's nothing to send." and listed "iamnbutler · natembp · Joins now".
• A's Mac was still set to a deployed directory that failed every sync: "The directory serves the tail49836a.ts.net tailnet, but this Mac is on tail93a054.ts.net." Nothing on A noticed B's directory, even after Refresh. A joined only by clicking Change… and pasting B's URL, which A had to get from B.
• On B's side nothing changed when A joined.

directory.adopt() in apps/host/src/directory.ts returns when isChosen(), so this is the designed rule. The dialog's promise and "Joins now" don't account for it.

Steps

1. Mac A has a directory configured, here one for another tailnet.
2. Mac B creates a directory on This Mac.
3. Read B's "Your team's directory is running" dialog, then A's Settings → Team.

Expected: the dialog says which Macs are on another directory and offers the URL to send them. A's Settings, while its own directory fails, offers the directory a teammate serves on this tailnet.

Map: ^109, ^108. Part of #550.

Found in the 2026-10-22 two-Mac pair study.