feat: Add browser-only launch mode for Kaspersky bypass

- Add `ui.launchBrowser` config option to launch browser directly
- Fix sidecar_manager to support packaged mode paths
- Set BROWSER_MODE env var for backend sidecar management
- Skip Electron window when browser-only mode enabled

Usage: Set `"ui": { "launchBrowser": true }` in config.json
to bypass Kaspersky blocking by using system browser instead.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

client/config.json

@@ -2,6 +2,9 @@
   "apiBaseUrl": "http://localhost:8000/api",
   "uploadTimeout": 600000,
   "appTitle": "Meeting Assistant",
+  "ui": {
+    "launchBrowser": false
+  },
   "whisper": {
     "model": "medium",
     "device": "cpu",