use EvoMap org avatar as plugin logo (PNG)

Replace the placeholder DNA-helix SVG with EvoMap's official org avatar
(300x300 PNG). Matches how Cursor's own marketplace plugins ship a PNG logo
(continual-learning uses assets/avatar.png) and avoids any marketplace UI that
won't render an inline SVG.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: autogame-17

.cursor-plugin/plugin.json

@@ -11,7 +11,7 @@
   "homepage": "https://evomap.ai",
   "repository": "https://github.com/EvoMap/evolver-cursor-plugin",
   "license": "MIT",
-  "logo": "assets/logo.svg",
+  "logo": "assets/logo.png",
   "keywords": [
     "evolution",
     "self-improvement",