Quit Must Not Mean Die
A normal GUI terminal is a process factory with a drawing surface glued on. Quit the app and the factory dies, so the shells die, so the editors die, so the four seats you were in the middle of die. That is reasonable for a text editor. It is hostile for a daily driver you walk away from twenty times a day.
Smolder splits the factory from the drawing. A session daemon, narrow on purpose, owns the PTYs, a bounded journal, and request receipts. The Mac app is a projection: it attaches, it draws, it may crash, it may quit with preservation on. The phone, later, is another projection. Neither projection is allowed to confuse its own lifetime with the lifetime of the jobs.
Narrow on Purpose
The daemon renders nothing. It calls no model. It loads no plugin. It holds no provider credential and no SSH credential. Those refusals are what keep it restartable and what keep a crash in the chrome from becoming a massacre in the jobs. A daemon that also draws is just the old glued-together app wearing a background-service costume.
Attachment is a private, versioned conversation between the app and the daemon — not a network API, not a prompt. The sibling door and the mobile gateway are different doors, later tracks, with different audiences. The daemon is the owner they all attach to. If you find yourself wanting the daemon to "just draw a little," you are gluing the factory back on.
Two Surfaces Already Depend on This
The Mac half of this quest will spend several more lessons on close, on what the owner's children inherit, on the journal, on restore, and on restarting the owner itself. The iOS half will spend a whole track on not treating a locked phone as a kill. Both of those sentences are false if the window still owns the process. Read this lesson as the load-bearing wall, not as Mac trivia.