feat(core): isolate dev and production environments

- Add IS_DEV_ENVIRONMENT flag to paths.ts for automatic detection
- Dev uses 'Gemini Nexus Dev' app data dir and '.geminiNexus-agent-dev' agent dir
- Dev proxy defaults to port 8046, production stays on 8045
- Move app.setName() before packetLogPath to ensure correct userData path
- Config, DB, logs, and ORPC packets fully isolated between dev and prod

src/preload.ts

@@ -10,16 +10,15 @@ import os from 'os';
 let sentryEnabled = false;
 try {
   const home = os.homedir();
+  const isDev = process.env.NODE_ENV === 'development';
+  const appName = isDev ? 'Gemini Nexus Dev' : 'Gemini Nexus';
   let appDataPath = '';
   if (process.platform === 'win32') {
-    appDataPath = path.join(
-      process.env.APPDATA || path.join(home, 'AppData', 'Roaming'),
-      'Gemini Nexus',
-    );
+    appDataPath = path.join(process.env.APPDATA || path.join(home, 'AppData', 'Roaming'), appName);
   } else if (process.platform === 'darwin') {
-    appDataPath = path.join(home, 'Library', 'Application Support', 'Gemini Nexus');
+    appDataPath = path.join(home, 'Library', 'Application Support', appName);
   } else {
-    appDataPath = path.join(home, '.config', 'Gemini Nexus');
+    appDataPath = path.join(home, '.config', appName);
   }
 
   const configPath = path.join(appDataPath, 'gui_config.json');