docs: say how to pick the lab back up

Co-Authored-By: Claude Opus 5 <[email protected]>

docs/classroom-v2-experiment.md

@@ -56,6 +56,12 @@ it, runs systemd as PID 1 so the session is supervised the way a real machine
 supervises it, and nests the session inside a headless sway so that `grim`
 can photograph it and a real pointer can be aimed at it.
 
+To resume: the lab is left running, built from the package, with Parent
+Call's test rig **not** started — so the classroom's broker settings are
+off and nothing can reach anything. `tools/lab/parent-call-rig up` brings
+the coordinator back, and it re-establishes and re-verifies the block on
+the church's networks before it will start.
+
 ```
 tools/lab/lab build          # the image
 tools/lab/from-package       # a fresh machine, the .deb, and nothing else
@@ -64,6 +70,8 @@ tools/lab/lab session        # compositor + Plasma session
 tools/lab/lab shot NAME      # docs/screenshots/NAME.png
 tools/lab/lab click X Y      # a real pointer press
 tools/lab/kwin-script FILE   # ask KWin what it believes about a window
+tools/lab/recovery-check     # every recovery property, measured
+tools/lab/parent-call-rig    # the real coordinator, safely walled off
 ```
 
 Every window measurement in this document came from `kwin-script`, not from