Tooltips after one second, and at once for the next button

From the development repository at b7ffe0e.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

docs/quickstart.md

@@ -70,7 +70,7 @@ rather than in the browser's storage.
 The toolbar holds the pen, text, eraser and hide tools, colours and
 line widths, the view commands (Fit, A4, Widen, Shrink, Extend), the
 host's page buttons (New, Image, Notebooks), your notebook, Keep, Export
-and Session.  Rest the pointer on any button for two seconds for its
+and Session.  Rest the pointer on any button for a second for its
 explanation.  Each participant writes on a layer of their own that
 nobody else can change.  The page is saved continuously to the current
 notebook, `Current.svg`; Keep makes a dated copy.  Rest the pen on an