docs: record Parent Call, the DVD migration and what is left to test

Three things in this window that a container cannot answer, and they are
now the top of the next-steps list: a real key pressed into Parent Call,
a television switched on after the computer, and a disc that plays.

Also brings the comments in the shared libraries up to date. The only
mention of sway left in the tree is the upgrade step that removes the
sway-era login shell from a room being upgraded.

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

lib/classroom_config.py

@@ -172,9 +172,10 @@ def ui_scale(config):
 
 # The scale the classroom's own GTK surfaces render at.
 #
-# UI_SCALE is applied by sway to the whole output (see classroom-scale),
+# UI_SCALE is applied to the whole output (see classroom-scale),
 # which scales Chrome, VLC and every other application along with the
-# dock. Our surfaces are measured in the same logical pixels sway is
+# panel. Our surfaces are measured in the same logical pixels the
+# compositor is
 # already scaling, so scaling them here as well would apply UI_SCALE
 # twice and the dock would come out half again too big.
 #

lib/classroom_icons.py

@@ -1,13 +1,14 @@
 """Icons that stay sharp when the compositor scales the session.
 
 new_from_file_at_scale rasterises an SVG at its *logical* size. Under
-sway's output scaling the compositor then enlarges that finished raster,
+output scaling the compositor then enlarges that finished raster,
 which is why icons went soft while the clock text and the dock surface
 stayed crisp: those are drawn by GTK at the display's real pixel
 density, and the icon was not.
 
-GTK 3 has no fractional scaling, so sway advertises the ceiling integer
-scale and scales the finished buffer down. Measured under sway: scale
+GTK 3 has no fractional scaling, so the compositor advertises the ceiling
+integer
+scale and scales the finished buffer down. Measured: scale
 factor 1 at output scale 1.0, and 2 at 1.25, 1.5 and 2.0.
 
 So the fix is to rasterise at size * scale_factor physical pixels and

lib/classroom_vlc.py

@@ -65,7 +65,8 @@ CLASSROOM_HOTKEYS = {
 
 # VLC dressed down to a playback surface. Verified against 3.0.23.
 PRESENTATION = (
-    # DVD mode is the whole display, and sway fullscreens the window the
+    # DVD mode is the whole display, and the compositor fullscreens the
+    # window the
     # moment it maps so no wallpaper is ever visible around it.
     "--fullscreen",
     # No menu bar, no panels, dark rather than light grey.