docs: close the checkpoint with the from-package reproduction

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

docs/classroom-v2-experiment.md

@@ -58,6 +58,7 @@ can photograph it and a real pointer can be aimed at it.
 
 ```
 tools/lab/lab build          # the image
+tools/lab/from-package       # a fresh machine, the .deb, and nothing else
 tools/lab/cold-start 3       # three complete cold starts, from nothing
 tools/lab/lab session        # compositor + Plasma session
 tools/lab/lab shot NAME      # docs/screenshots/NAME.png
@@ -574,9 +575,21 @@ The existing Debian classroom test VM should be kept.
 * Secondary windows, print dialog, notifications, fullscreen, themes, lockdown
   all verified on a running session.
 * Audio policy written with the failing room as a test.
-* Cold starts repeated.
+* Cold starts repeated: eleven, identical.
+* Package built, and the file conflict and the stale `postinst` it exposed
+  both fixed.
+* `tools/lab/from-package` run: fresh machine, `.deb`, session up, both
+  applications launched, one button each.
 
-**Next**: SDDM autologin; move the file list in `tools/build-release.sh` to
+**Next**, in order:
-the Plasma layout and build a `0.1.45~plasma1` package on its own channel;
+
-Plasma display scaling at 1.25 and 1.5; then a real VM for DVD, audio and
+1. Port `classroom-window` off sway so the DVD player is whole. It is the
-performance.
+   last thing on this branch that still speaks a compositor the classroom
+   no longer runs.
+2. Publish `0.1.45~plasma1` to a channel of its own, the way the Hyprland
+   milestone did, so a stable or canary room can never be offered it.
+3. Bench-test SDDM: autologin, and that ending the session brings the
+   classroom back rather than a shell.
+4. On real hardware: a DVD, a television switched on after the computer,
+   printing to Elmer, display scaling at 1.25 and 1.5, and a weekend of
+   uptime.

tools/lab/from-package

@@ -0,0 +1,52 @@
+#!/bin/bash
+# The whole thing, from nothing, the way a classroom would get it: a fresh
+# machine, the built .deb, and the session started from what it installed.
+# No developer install script anywhere in the path.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/../.." && pwd)"
+LAB="$ROOT/tools/lab/lab"
+DEB="${1:-$(ls -t "$ROOT"/dist/ekklesia-classroom_*_amd64.deb | head -1)}"
+NAME="${LAB_NAME:-classroom-v2-lab}"
+
+echo "installing $(basename "$DEB")"
+"$LAB" up >/dev/null
+
+docker exec "$NAME" sh -c '
+    printf "#!/bin/sh\nexit 101\n" > /usr/sbin/policy-rc.d
+    chmod +x /usr/sbin/policy-rc.d
+    apt-get update -qq >/dev/null 2>&1'
+
+docker exec "$NAME" sh -c "
+    DEBIAN_FRONTEND=noninteractive dpkg -i '/srv/classroom/${DEB#$ROOT/}' \
+        >/dev/null 2>&1 || true
+    DEBIAN_FRONTEND=noninteractive apt-get -y -qq -f install >/dev/null 2>&1
+    DEBIAN_FRONTEND=noninteractive dpkg --configure ekklesia-classroom >/dev/null 2>&1
+    rm -f /usr/sbin/policy-rc.d"
+
+state=$(docker exec "$NAME" dpkg-query -W -f='${db:Status-Abbrev}' ekklesia-classroom)
+echo "package state: $state"
+
+# environment.d is read when the user manager starts, so it starts after.
+docker exec "$NAME" systemctl restart [email protected]
+sleep 4
+
+"$LAB" session >/dev/null
+sleep 8
+
+check() { printf '  %-46s %s\n' "$1" "$2"; }
+env_dirs=$(docker exec -u classroom -e XDG_RUNTIME_DIR=/run/user/1000 \
+    -e DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus "$NAME" \
+    systemctl --user show-environment 2>/dev/null | grep '^XDG_CONFIG_DIRS=' || true)
+
+check "package installed" "$state"
+check "session config path" "${env_dirs:-NOT SET}"
+check "plasmashell" "$(docker exec "$NAME" pgrep -c -x plasmashell || echo 0)"
+check "kwin" "$(docker exec "$NAME" pgrep -c -x kwin_wayland || echo 0)"
+check "panel applets" "$(docker exec "$NAME" sh -c 'grep -c "^plugin=" /home/classroom/.config/plasma-org.kde.plasma.desktop-appletsrc' || echo 0)"
+check "panel restart policy" "$(docker exec -u classroom -e XDG_RUNTIME_DIR=/run/user/1000 \
+    -e DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus "$NAME" \
+    systemctl --user show plasma-plasmashell.service -p Restart --value)"
+check "audio policy" "$(docker exec -u classroom -e XDG_RUNTIME_DIR=/run/user/1000 \
+    -e DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus "$NAME" \
+    systemctl --user is-active ekklesia-classroom-audio.service || true)"