feat: Node.js path scanning + manual path input + git HTTPS auto-fix (v0.4.2)

- Add scan_node_paths: auto-scan C/D/E/F/G drives for Node.js installations
- Add check_node_at_path: verify Node.js at user-specified directory
- Add save_custom_node_path: persist custom path to ~/.openclaw/clawpanel.json
- enhanced_path() now loads saved custom path and applies to all commands
- Windows enhanced_path: scan Program Files, LOCALAPPDATA, APPDATA, common drives
- Auto git config HTTPS-instead-of-SSH before npm install (fixes exit 128)
- Setup page: auto-scan button + manual path input when Node.js not detected
- Error diagnosis: add EPERM, MODULE_NOT_FOUND, SSH publickey patterns
- README: expanded troubleshooting section

package.json

@@ -1,6 +1,6 @@
 {
   "name": "clawpanel",
-  "version": "0.4.1",
+  "version": "0.4.2",
   "private": true,
   "description": "ClawPanel - OpenClaw 可视化管理面板，基于 Tauri v2 的跨平台桌面应用",
   "type": "module",