Toggle state in the icon's shape, not the theme's colours (#74)

4ed2d59 drew a pressed toggle in each theme's accent colour; the themes'
colours were not to change. Back as they were, pinned rows included. The
read button carries its state in its shape instead, as the pin does with
outline and solid: a tick when read, the envelope when not, where before
it showed the action (the envelope on a read item).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/contrast.js

@@ -27,7 +27,6 @@ const RULES = [
   ['dim', ['bg', 'panel', 'panel2'], 4.5],       // metadata, labels
   ['faint', ['bg', 'panel', 'panel2'], 4.5],     // hints, column headings, the status bar
   ['accent', ['bg', 'panel'], 4.5],              // links, in the list and the reader
-  ['accent', ['panel2', 'raise'], 3],            // a toggle that is on: pinned, read
   ['ink', ['accent'], 4.5],                      // a primary button's label
   ['ink', ['accent2'], 4.5],                     // the unread count on its badge
   ['accent2', ['bg', 'panel', 'raise'], 3],      // the unread dot, the EQ bars, download bars