ecc2a9c574
Measured on tor-ms22: the layering here is kitty -> tmux (on the host) -> docker exec -> pi (in the container), with two clients attached to one tmux session. Test OSC sequences written straight to pi's tty produced no notification on the remote client; the local client is still unobserved. Most likely tmux is dropping OSC types it does not implement — reaching the outer terminal needs tmux's DCS passthrough (ESC P tmux; ... ESC \, inner ESC doubled) plus allow-passthrough on, which is not the default and is not implemented here. The point worth keeping is structural, not incidental: the container can see NEITHER layer. KITTY_WINDOW_ID is absent because docker exec does not forward it, and TMUX is absent because tmux runs one level further out on the host. So a containerised client cannot detect the terminal it is speaking to or the multiplexer it must speak through, and autodetection is not merely unreliable here — it is blind. Explicit configuration is the only route, which is why the previous commit added forced kitty/osc777 modes. No behaviour or defaults changed: in-TUI notify remains the default and the terminal path stays opt-in. Also flagged the unsettled routing question — a pane's output reaches every attached client, so a work laptop and a home machine would both ping from one arriving ask.