docs: the guide around four things and two screens, new screenshots, the plan closed

The guide opens with documents, cards, notes and diary entries, and the
documents and plan screens, then walks the day with the scratchpad, the
info sheet and cards linked both ways. The README and the wiki's home say
the same in short, and show the scratchpad and the info sheet. The
screenshot script drops its Alt keys and takes both. PLAN.md records the
simplification's slices, what was left of its navigation fixes, and the
backlog fitted to the model.

docs/wiki/Writing.md

@@ -63,8 +63,11 @@ desktop lowers its own; `Q`, `q` or `Esc` raises it again, and what was on
 screen is as it was. `Ctrl-Q` works from anywhere, the editor included: the
 scratchpad comes down with the last note being written, at its end, and
 `Ctrl-Q` again puts it away and goes back to the document, still writing where
-it was left. Firefox quits on `Ctrl-Q`, so there it is `Q` only. Its notes have no name, no space and no folder: a note is
-a body and the time it was last touched, newest on top.
+it was left. Firefox quits on `Ctrl-Q`, so there it is `Q` only. Its notes have no name,
+no space and no folder: a note is a body and the time it was last touched,
+newest on top.
+
+![The scratchpad, lowered over the documents](../images/scratch.png)
 
 | key | what it does |
 | --- | --- |