fix: macOS PATH detection + npm install error diagnosis (v0.4.1)

- Fix macOS Node.js/npm/openclaw detection by adding enhanced_path() with common install locations (/usr/local/bin, /opt/homebrew/bin, ~/.nvm, ~/.volta, etc.)
- Add npm install error diagnosis: auto-detect git missing (exit 128), ENOENT, permission denied, network errors, cache corruption
- Show macOS-specific hint when Node.js detection fails in setup page
- Add shared error-diagnosis.js module used by both setup and services pages
- Add troubleshooting section to README.md
- Bump version to 0.4.1

src/lib/error-diagnosis.js

@@ -0,0 +1,67 @@
+/**
+ * npm install / upgrade 常见错误诊断
+ * 解析 npm 错误信息，返回用户友好的提示和修复建议
+ */
+
+/**
+ * @param {string} errStr - npm 错误输出
+ * @returns {{ title: string, hint?: string, command?: string }}
+ */
+export function diagnoseInstallError(errStr) {
+  const s = errStr.toLowerCase()
+
+  // git 未安装（exit 128 + access rights）
+  if (s.includes('code 128') || s.includes('exit 128') || s.includes('access rights')) {
+    return {
+      title: '安装失败 — 需要安装 Git',
+      hint: '部分依赖需要通过 Git 下载。请先安装 Git 后重试。',
+      command: '下载 Git: https://git-scm.com/downloads',
+    }
+  }
+
+  // ENOENT（文件找不到）
+  if (s.includes('enoent') || s.includes('-4058') || s.includes('code -4058')) {
+    return {
+      title: '安装失败 — 文件访问错误',
+      hint: '尝试以管理员身份运行 ClawPanel，或在终端手动安装：',
+      command: 'npm install -g @qingchencloud/openclaw-zh --registry https://registry.npmmirror.com',
+    }
+  }
+
+  // 权限不足（EACCES / EPERM）
+  if (s.includes('eacces') || s.includes('eperm') || s.includes('permission denied')) {
+    const isMac = navigator.platform?.includes('Mac') || navigator.userAgent?.includes('Mac')
+    return {
+      title: '安装失败 — 权限不足',
+      hint: isMac ? '请在终端使用 sudo 安装：' : '请以管理员身份打开终端安装：',
+      command: isMac
+        ? 'sudo npm install -g @qingchencloud/openclaw-zh --registry https://registry.npmmirror.com'
+        : 'npm install -g @qingchencloud/openclaw-zh --registry https://registry.npmmirror.com',
+    }
+  }
+
+  // 网络错误
+  if (s.includes('etimedout') || s.includes('econnrefused') || s.includes('enotfound')
+    || s.includes('network') || s.includes('fetch failed') || s.includes('socket hang up')) {
+    return {
+      title: '安装失败 — 网络连接错误',
+      hint: '请检查网络连接，或尝试切换 npm 镜像源后重试。',
+    }
+  }
+
+  // npm 缓存损坏
+  if (s.includes('integrity') || s.includes('sha512') || s.includes('cache')) {
+    return {
+      title: '安装失败 — npm 缓存异常',
+      hint: '尝试清理 npm 缓存后重试：',
+      command: 'npm cache clean --force',
+    }
+  }
+
+  // 通用 fallback
+  return {
+    title: '安装失败',
+    hint: '请在终端手动尝试安装，查看完整错误信息：',
+    command: 'npm install -g @qingchencloud/openclaw-zh --registry https://registry.npmmirror.com',
+  }
+}