Screens 1 and 4 running as TUIOS panes: reply screen, adopt-or-create launcher, layout script

docs/TUIOS-RUNBOOK.md

@@ -98,3 +98,24 @@ tuios send-keys    -s "$TUIOS_SESSION" -w harness-check Down --repeat 2
 ```
 
 If the pane shows what you expect after the keys, it works where it will be used.
+
+## Opening the screens
+
+The session for this project is named **`paperclip-harness`**. The scripts take that name
+themselves; they never read `TUIOS_SESSION`, because that is the session of the pane you
+happen to be typing in, and using it once put a screen in the wrong session.
+
+```
+bin/layout                       # every screen, in order, adopting what is already there
+bin/screen tree                  # one screen
+bin/screen reply AUD-162
+```
+
+Both are idempotent: a second run focuses the pane that is already running that screen. The
+pane is a shell that starts the program and returns to the shell when it exits, so a pane
+never closes itself and the workspace keeps the pane that stops it being deleted.
+
+Measured: closing the last pane on a workspace leaves the number but **erases the
+workspace's name**. Reopening therefore falls back to the first empty workspace and renames
+it, which is why `bin/screen` prints either `created` or `adopted` and the workspace it
+used. Nothing stores a workspace number.