Add shared Icon primitive and controlled glyph vocabulary (Carbon, filled)

styles/tokens.css

@@ -25,6 +25,13 @@
   --space-8: 48px;
   --space-9: 64px;
 
+  /* Iconography — Carbon icon scale (arch 09 §5.3). Icons are SVG drawn with
+     fill: currentColor; 16px is the default, paired to 14px body text. */
+  --icon-sm: 16px;
+  --icon-md: 20px;
+  --icon-lg: 24px;
+  --icon-xl: 32px;
+
   /* Shape — square chrome (icons keep their own rounded geometry) */
   --radius: 0px;
   --border-width: 1px;
@@ -42,6 +49,9 @@
   --support-error: #da1e28;
   --support-success: #198038;
   --support-warning: #f1c21b;
+  /* Warning foreground: the raw yellow fails contrast on light surfaces, so status
+     glyphs/text use a darkened amber. Dark theme keeps the yellow (legible on dark). */
+  --support-warning-fg: #8a6d00;
   --support-info: #0043ce;
   --on-status: #ffffff;
 
@@ -74,6 +84,7 @@
   --support-error: #fa4d56;
   --support-success: #42be65;
   --support-warning: #f1c21b;
+  --support-warning-fg: #f1c21b;
   --support-info: #78a9ff;
   --on-status: #161616;
 }