fix: deliver test notifications into the classroom session

The classroom desktop belongs to the classroom user and mako sits on
that user's D-Bus session. An administrator over SSH is in a different
session where nothing owns org.freedesktop.Notifications, so notify-send
asked D-Bus to start a second mako, which had no display to open and
timed out with NoReply.

Find the running sway process for the classroom user and deliver into
its session instead. XDG_RUNTIME_DIR and the bus address are read from
that process, falling back to /run/user/<uid> and its bus socket when
the environment cannot be read — root has ptrace access on the endpoint,
but that is not somewhere to be brittle. The Wayland display is read the
same way, and failing that from the wayland-N.lock sway holds open, so
no socket name is ever assumed. notify-send only needs the bus, so a
display that cannot be resolved is not worth refusing to send over.

Refuses to send when mako is not already running, rather than letting
D-Bus start one, and says plainly what is wrong when there is no
session, no privileges, or no bus socket. --dry-run reports what it
resolved without sending.

Behaviour inside the session is unchanged, and the sample notifications
and styling are untouched.

The tests stand a real background process in for sway so /proc/<pid>/environ
is genuine rather than mocked, and cover both invocation paths plus the
fallbacks and every refusal. The build runs them.

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

tools/build-release.sh

@@ -24,7 +24,7 @@ OUTPUT="$ROOT/dist/ekklesia-classroom_${VERSION}_amd64.deb"
 # drift out of date as classroom commands are added.
 echo "Validating sources"
 
-for script in "$ROOT/packaging/debian/postinst" "$ROOT"/scripts/*; do
+for script in "$ROOT/packaging/debian/postinst" "$ROOT"/scripts/* "$ROOT"/tests/*; do
     [[ -f "$script" ]] || continue
 
     case "$(head -n 1 "$script")" in
@@ -52,6 +52,17 @@ done
 find "$ROOT/scripts" "$ROOT/lib" \
     -name '__pycache__' -type d -prune -exec rm -rf {} + 2>/dev/null || true
 
+for test in "$ROOT"/tests/test-*.sh; do
+    [[ -x "$test" ]] || continue
+
+    echo "Running $(basename "$test")"
+    "$test" > /dev/null || {
+        echo "Tests failed. Run it directly to see why:"
+        echo "  $test"
+        exit 1
+    }
+done
+
 echo "Building Ekklesia Classroom ${VERSION}"
 
 # Always construct the package from clean canonical sources.