docs: turn the accepted panel design into an enforceable contract

panel-redesign.md is rewritten for the accepted direction: three layers
(Bulma as shipped, adapters, own sp- components), the page layouts, what
an implementer must not do, and how that is enforced — guard tests that
land before any template, a design-first CI step, and acceptance by
evidence (test output plus a screenshot of every page beside its mockup,
reviewed by a model that did not write the step).

A components page shows every building block in every state; a screen
may be built from nothing else. panel/check.py lints the mockups against
the contract (class vocabulary, CSS bans on !important, id and page
selectors and stray widths, page structure) and writes
panel/outlines.json, the per-screen component skeleton an implementation
is compared with, so a different design cannot pass as this one.

Own modifier classes now carry the sp- prefix (sp-warn, sp-fail, sp-big,
sp-danger-zone, ...) so the vocabulary is machine-checkable; the lint
also caught a width set outside the layout in the mockup's own CSS.

Agent rule .cursor/rules/panel-design.mdc; roadmap row and section
updated (0/15, still candidate).

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

docs/assets/panel-redesign/panel/settings.html

@@ -107,7 +107,7 @@
             <div class="sp-box-head"><span class="sp-no">03</span><h2>Sending rate limits</h2><div class="sp-end">Read-only</div></div>
             <div class="sp-box-body">
               <dl class="sp-facts">
-                <div><dt>Level 1 · per client IP</dt><dd class="is-big">600 / h</dd><dd class="sp-muted">Set in <code>.env</code>; restart to change. Nothing below may exceed it.</dd></div>
+                <div><dt>Level 1 · per client IP</dt><dd class="sp-big">600 / h</dd><dd class="sp-muted">Set in <code>.env</code>; restart to change. Nothing below may exceed it.</dd></div>
                 <div><dt>Level 2 · domain, application</dt><dd>Set on each <a href="out-domain-settings.html#limit">domain</a> and <a href="out-app.html">application</a>.</dd></div>
               </dl>
             </div>