docs: temporary workspace restore, the admin link bubble, and Sunday's checks

wonder-ink.md: where WonderInk keeps its sign-in (Basic auth in a cookie)
and why only tabs are restored; what comes back and what never does; what
counts as use; when it is not restored; the test-only override. And the
link bubble teachers saw: WonderInk's CKEditor 5 for Admin accounts,
where a plain click on a link is an editing click by design; Viewers get
one-click links, measured on the real Saul lesson, and Wonder Ink does
not override the editor.

The manual says closing still signs you out and recent tabs come back
for two hours. testing.md has the Little Waders checklist.

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

docs/screenshots/README.md

@@ -159,6 +159,7 @@ Under the lab's real Plasma session, driven with the pointer. See
 | `pic-preview-default`, `pic-preview-half-topleft` | a picture in a tab of its own, laid out on Letter: as large as fits, then 50% top left (0.2.6.2) |
 | `print-image-menu` | right-click on a picture inside a lesson: **Print image…** and **Print page…**; on the words there is only Print page (0.2.6.3) |
 | `print-image-bw-half-topleft` | Print image on a signed-in picture, 50% top left, Black and white — the preview grey, as the job CUPS kept was (0.2.6.3) |
+| `workspace-restored` | Wonder Ink reopened after an accidental close: the lesson's WonderInk tab at its sign-in page, its slide in front, its PDF behind (0.2.6.4, the real site) |
 
 ## Failures, kept