Green instead of gold, and a leaf that reads at 16px

The brand accent was rune gold. It is now mallorn green: --gold becomes
--leaf in tokens.css and everywhere it resolved, and the mark's wafer is
the green of the leaves lembas travels wrapped in rather than the biscuit
inside. Yellow is left to mean exactly one thing in the interface -- a
warning -- instead of two.

Two knock-on choices the rename forced:

  - Code keywords move from the brand accent to --warning. Strings are
    --success, which is green; keywords in leaf green beside them is not
    a colour scheme.
  - --success itself leans teal now. Two greens a hue apart read as one
    colour rendered badly, and an unread dot has to be tellable from a
    brand badge at a glance.

The mark is redrawn, not just recoloured. The blade is ovate -- widest a
third up from the base, rounded where the stem meets it, drawn out only
at the tip -- because the old one was pointed at both ends and read as an
eye. It is also much larger relative to the tile: at 16px the silhouette
is all that survives, and a small leaf on a large tile is a green square
with a smudge on it. Veins sweep towards the tip and shorten as the blade
narrows. The score cross is thinner and fainter so it stays texture.

A single diagonal score was tried first and rejected: behind a diagonal
leaf it does not read as scoring, it reads as a line struck through the
mark.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

src/lembas/web/templates/admin/model_detail.html

@@ -38,7 +38,7 @@
     </div>
     <div class="btn-row">
       {% if model.model_id == default_model %}
-      <span class="badge badge--gold">{{ icon("star", "icon--sm") }} default model</span>
+      <span class="badge badge--leaf">{{ icon("star", "icon--sm") }} default model</span>
       {% else %}
       <form method="post" action="/admin/models/{{ model.id }}/default">
         <button class="btn btn--sm" type="submit">