feat: Wonder Ink looks like the classroom, and its preview shows the page

The tab strip is drawn from the classroom's own palette, the one the
panel, Parent Call and Presentations read: larger titles, an accent
under the active tab, worksheets marked with a document icon. Its one
corner widget is the lesson's size and Print — not a new-tab button. With
one tab the strip stays hidden, as before; a change of size shows a
moment's badge instead, and the right-click menu and keys still work.
The window is named "Lesson — Wonder Ink" and carries its own icon.

The print preview showed "Page 1 could not be shown" in the real
session while printing correctly: poppler 25.03 does not write to stdout
when asked for "-" — it writes a file called "-.png" into the current
directory, which for Wonder Ink is the teacher's home. Pages are now
rendered into a directory of their own, and the lab print check fails
any preview that does not draw its page.

The teacher's manual has lesson size and printing.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

tools/lab/wonderink-print-check

@@ -100,6 +100,13 @@ for scenario in "${scenarios[@]}"; do
 
     judge "Wonder Ink did not crash, and exited by itself" exited_cleanly
 
+    # The preview has to SHOW the page, not merely count it. A preview
+    # that printed the right thing while showing a blank was what the
+    # first version of this check let through.
+    if said 'PREVIEW '; then
+        judge "the preview drew the page it will print" "! grep 'PREVIEW ' <<< \"\$out\" | grep -q 'shown=False'"
+    fi
+
     case "$scenario" in
     web)
         judge "the preview showed the lesson, 3 Letter pages, Elmer chosen" \