The Local Pane Model Has No Wrap
Once the daemon owns the process, the Mac app still has to be a terminal you can live in. That starts with a rule that looks small and is not: one PTY stream per pane. The local pane model has no "wrap in tmux" option. An external multiplexer composing local panes into one screen is the seam this quest opened with — two programs you do not own, a serialized rectangle, selection as a parser, restore as a guess. Owning the pane means that multiplexer is not in the path from process to pixel.
SwiftTerm draws that one stream: one terminal view per pane, configured, never patched. The emulator is embedded. The pixels are yours. Nested splits, drag, maximize, a tab that moves as a tree — those are native objects sitting on top of that one-to-one mapping. If a multiplexer sat between, every one of those objects would be a screenshot of someone else's grid.
Remote tmux Is a Different Sentence
A far host you do not sit in front of may still run tmux. Until the family owns daemons on those hosts too, that is an honest multiplexer for a machine that has no Smolder owner. You SSH there, you attach, you live in their screen protocol because that host has no pane objects to give you. That sentence does not license wrapping the local window. Local panes are never a tmux client of themselves.
The failure mode is a setting that says "use tmux for local splits, it is fine, we already speak it for remote." Same English word, two owners. Locally, Smolder is the multiplexer. Remotely, someone else's tmux is a guest inside one pane's stream. Keep those in different mouths. A guest inside a pane is content. A wrapper around local panes is a relapse.
One View, One Stream, One Owner
The daemon holds the PTY. The app holds a SwiftTerm view that reads that PTY's output and writes that PTY's input, under lease. There is no second grid. There is no local session server composing panes out of cells. Split is a native split of views, each view bound to its own PTY. That is why a sibling can ask for a folder in a new pane without pretending to type, and why a tab can move as a tree without starting placeholder shells.
This lesson is the desktop craft's floor. The rest of the track — tree, moveable tab, arrangements, chrome — assumes the mapping. Break the mapping to "get tmux features back" and you have not added features. You have sold the pane back to a stream.