Bump to 1.2.0 for new release

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "dj-visualizer",
-  "version": "1.1.0",
+  "version": "1.2.0",
   "description": "Audio-reactive fractal & abstract visualizer for external display (Mac)",
   "main": "main.js",
   "author": {