Apply GitHub iconography to workshop diagrams (#2456)

Author: Copilot

scripts/check-svg-visual-language.js

@@ -11,7 +11,7 @@
  * Checks:
  *   1. Accessibility — root <svg> must have role="img" and a non-empty,
  *      resolvable accessible name.
- *   2. Icon characters — Unicode status/icon characters (✓ ✗ ✕ ⚡ 🕐 ▶ ►)
+ *   2. Icon characters — Unicode status/icon characters (✓ ✗ ✕ ⚡ ⏰ 🕐 ▶ ►)
  *      must not appear in SVG <text> nodes used as visual indicators.
  *      Use unmodified Primer Octicon paths instead (see guidelines).
  *   3. Canvas dimensions — light/dark variant files (*-light.svg, *-dark.svg)
@@ -148,6 +148,7 @@ const ICON_CHARS = {
   '✕': 'the unmodified x-circle Octicon path',
   '✘': 'the unmodified x-circle Octicon path',
   '⚡': 'the unmodified zap Octicon path',
+  '⏰': 'the unmodified clock Octicon path',
   '🕐': 'the unmodified clock Octicon path',
   '🕛': 'the unmodified clock Octicon path',
   '▶': 'the unmodified play Octicon path',

scripts/check-svg-visual-language.test.js

@@ -104,11 +104,13 @@ test('rejects Unicode indicators and incorrect explicit state colors', () => {
       role="img" aria-label="Bad state">
       <rect data-state="error" fill="#3fb950" />
       <text>✓</text>
+      <text>⏰</text>
     </svg>`
   );
 
   assert.equal(result.status, 1);
   assert.match(result.stderr, /Unicode icon character/);
+  assert.match(result.stderr, /"⏰"/);
   assert.match(result.stderr, /data-state="error"/);
   assert.match(result.stderr, /Expected Primer dark-mode color: #f85149/);
 });