feat: complete rebranding to Gemini Nexus with improved UI, proxies and documentation

package.json

@@ -1,8 +1,8 @@
 {
-  "name": "antigravity-manager",
-  "productName": "Antigravity Manager",
+  "name": "gemini-nexus",
+  "productName": "Gemini Nexus",
   "version": "0.11.1",
-  "description": "Antigravity Manager - Electron App",
+  "description": "Gemini Nexus - Electron App",
   "main": ".vite/build/main.js",
   "private": true,
   "scripts": {