complete oklch migration: zero named palette refs remain

- 01-asw.css: 20 new tokens (14 --syntax-*, 6 utility: print, absolute, high-contrast)
- Layers 02-09: all 30 TODO refs replaced with semantic/syntax tokens
- Zero --gray-N, --green-N, --blue-N, --red-N, --yellow-N in layers 02-09
- Palette-hue knob now controls entire site. Syntax highlighting uses fixed oklch hues.

assets/css/layers/08-layout.css

@@ -542,8 +542,8 @@ main[data-layout="prose"],
 /* Print styles */
 @media print {
   [data-layout="report"] {
-    --surface: var(--gray-0);   /* TODO: map to semantic token — overriding --surface for print; no alias for gray-0 as "print-white" */
-    --text: var(--gray-15);     /* TODO: map to semantic token — overriding --text for print; no alias for gray-15 as "print-black" */
+    --surface: var(--print-surface);
+    --text: var(--print-text);
     font-size: 11pt;
   }