feat: minimize and restore windows the way a desktop does

The scratchpad technically minimized Chrome, but sway hands scratchpad
windows back floating, so restoring gave a draggable window instead of
the maximized one the user put away. Park windows on a hidden workspace
as ordinary tiled containers instead, and move them back to the visible
workspace on restore.

classroom-window carries the whole state machine, so the dock buttons
and Super+M share one implementation:

  not running  -> launch
  unfocused    -> focus
  focused      -> minimize
  minimized    -> restore, tiled and maximized

Fullscreen is dropped on the way out, since a container parked while
still fullscreen keeps drawing over everything else. floating disable on
the way back also rescues windows left floating by the old scratchpad
path.

Super+Shift+M restores the newest minimized window, so nothing can get
stranded on the hidden workspace.

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

tools/build-release.sh

@@ -20,6 +20,38 @@ fi
 STAGE="$ROOT/packaging/root"
 OUTPUT="$ROOT/dist/ekklesia-classroom_${VERSION}_amd64.deb"
 
+# Syntax check everything the package ships, by shebang, so this cannot
+# drift out of date as classroom commands are added.
+echo "Validating sources"
+
+for script in "$ROOT/packaging/debian/postinst" "$ROOT"/scripts/*; do
+    [[ -f "$script" ]] || continue
+
+    case "$(head -n 1 "$script")" in
+        *python3*)
+            python3 -m py_compile "$script"
+            ;;
+        *bash*|*bin/sh*)
+            bash -n "$script"
+            ;;
+    esac
+done
+
+for module in "$ROOT"/lib/*.py; do
+    [[ -f "$module" ]] || continue
+
+    python3 -m py_compile "$module"
+done
+
+for policy in "$ROOT"/config/chrome/policies/*/*.json; do
+    [[ -f "$policy" ]] || continue
+
+    python3 -c 'import json, sys; json.load(open(sys.argv[1]))' "$policy"
+done
+
+find "$ROOT/scripts" "$ROOT/lib" \
+    -name '__pycache__' -type d -prune -exec rm -rf {} + 2>/dev/null || true
+
 echo "Building Ekklesia Classroom ${VERSION}"
 
 # Always construct the package from clean canonical sources.
@@ -54,6 +86,10 @@ install -Dm755 \
     "$ROOT/scripts/classroom-browser" \
     "$STAGE/usr/local/bin/classroom-browser"
 
+install -Dm755 \
+    "$ROOT/scripts/classroom-window" \
+    "$STAGE/usr/local/bin/classroom-window"
+
 install -Dm644 \
     "$ROOT/config/wallpapers/classroom-default.png" \
     "$STAGE/usr/share/backgrounds/ekklesia/classroom-default.png"