docs: point at the screenshot index

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

docs/classroom-v2-experiment.md

@@ -457,17 +457,9 @@ did.
 
 ## Screenshots
 
-In `docs/screenshots/`.
+Twenty-nine, in `docs/screenshots/`, indexed in
-
+[screenshots/README.md](screenshots/README.md) — including the two that
-`v2-idle-desktop` the idle desktop · `v2-light-bar` / `v2-dark-bar` the same
+record failures rather than successes.
-bar in both themes · `state-1-closed` closed · `state-3-behind` active beside
-running · `state-4-minimized` · `state-5-restored` · `v2-testpage` a
-maximised browser · `v2-secondary-window` a window a page opened, floating ·
-`v2-print-dialog` · `v2-notification-crop` · `v2-fullscreen` · `recover-panel`
-the bar rebuilt from nothing · `lock-desktop-rmb`, `lock-panel-rmb`,
-`lock-krunner` the lockdown · `v2-from-package` the desktop as installed
-from the `.deb` · `v2-layershell` a gtk-layer-shell overlay under KWin, which
-is what the DVD player's loading cover is made of.
 
 ## Not done, and honest about it