Retire forbidAbsolutes() and forbidOpacityInk() from the design guard

Plan step 41 review (the user, 2026-09-15): without Tailwind, bg-white and
text-on-surface/60 compile to nothing like any other utility, so family (i)
now reports every colour utility on an M3 role, a 1.x ink name
(text-meta, border-divider), white, black or current, with or without an
opacity, each with its 2.0.0 replacement (an md-ink-* class, <x-divider>,
<x-surface level>, md-state-layer or the role's var()). Check (iii) reads
named colours anywhere in a declaration's value (border: 1px solid white),
hex codes only in values (an id like #add no longer matches), and masks
strings and url() contents first.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Fixtures/design-guard/app-css/app.css

@@ -18,6 +18,19 @@
     border: 0;
 }
 
+/* white in a comment is ignored, and so is #fff */
+.quiet::before {
+    content: "white";
+    border: 1px solid white;
+    outline-color: #fff;
+    background: url(data:image/svg+xml;utf8,<svg fill='black'></svg>);
+}
+
+#add-button, .red-banner {
+    color: transparent;
+    fill: currentColor;
+}
+
 @media (min-width: 700px) {
     .card {
         display: flex;