chore(electron): sync version to 1.8.15

Align Electron app version with server release for consistent
auto-update delivery.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

electron/package.json

@@ -1,7 +1,7 @@
 {
   "name": "gaming-hub-desktop",
   "productName": "Gaming Hub",
-  "version": "1.8.0",
+  "version": "1.8.15",
   "description": "Gaming Hub Desktop App mit Ad-Blocker",
   "author": "Gaming Hub",
   "main": "main.js",