fix(vscode): use the Signal Current mark, not a one-off whale

The extension shipped its own slate/sky whale that existed nowhere else in
the product. The canonical mark is Signal Current — `web/app/icon.svg` and
the WHALE_BODY / WHALE_CURRENT constants in `web/components/whale.tsx`,
described there as "from the managed Codewhale product contract."

Replaced with the canonical paths (verified byte-identical to icon.svg) on
the product color tokens: signal gold #F6C453 and current cyan #48D7FF.
A comment names the two other copies so the next person keeps all three in
step rather than inventing a fourth.

extensions/vscode/media/codewhale.svg

@@ -1,6 +1,11 @@
-<svg width="128" height="128" viewBox="0 0 128 128" xmlns="http://www.w3.org/2000/svg" role="img" aria-label="CodeWhale">
-  <rect width="128" height="128" rx="20" fill="#0f172a"/>
-  <path d="M26 72c0-21 17-38 38-38h21c10 0 19 6 23 15 2 4 6 7 10 8-5 4-11 6-18 6h-2c-1 23-20 41-43 41H34c-7 0-12-5-12-12V80c0-4 3-8 8-8h-4z" fill="#38bdf8"/>
-  <circle cx="82" cy="56" r="5" fill="#0f172a"/>
-  <path d="M42 85h36M45 96h25" stroke="#0f172a" stroke-width="6" stroke-linecap="round"/>
+<!-- Signal Current — the canonical Codewhale mark, from the managed product
+     contract. Paths are identical to web/app/icon.svg and the WHALE_BODY /
+     WHALE_CURRENT constants in web/components/whale.tsx; keep all three in
+     step. Colors are the product tokens: signal gold and current cyan. -->
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 180 180" width="180" height="180" role="img" aria-label="Codewhale">
+  <rect width="180" height="180" rx="38" fill="#08111C"/>
+  <g transform="translate(26 26) scale(2)">
+    <path fill="#F6C453" d="M7 57c9-13 21-15 25-25 3-7-1-12-10-16 6-1 11 1 14 6 3-6 10-11 19-13-1 10-5 17-12 21-4 3-5 8-8 14-5 9-15 14-28 13Z"/>
+    <path fill="#48D7FF" d="M28 58c10-8 15-15 17-26 4 8 2 18-3 26H28Z"/>
+  </g>
 </svg>