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-tauri/src/commands/config.rs

@@ -39,6 +39,7 @@ fn npm_command() -> Command {
     {
         let mut cmd = Command::new("npm");
         cmd.args(["--registry", &registry]);
+        cmd.env("PATH", super::enhanced_path());
         cmd
     }
 }
@@ -635,6 +636,8 @@ pub fn check_node() -> Result<Value, String> {
     let mut result = serde_json::Map::new();
     let mut cmd = Command::new("node");
     cmd.arg("--version");
+    #[cfg(not(target_os = "windows"))]
+    cmd.env("PATH", super::enhanced_path());
     #[cfg(target_os = "windows")]
     cmd.creation_flags(0x08000000); // CREATE_NO_WINDOW
     match cmd.output() {

src-tauri/src/commands/mod.rs

@@ -13,3 +13,25 @@ pub mod service;
 pub fn openclaw_dir() -> PathBuf {
     dirs::home_dir().unwrap_or_default().join(".openclaw")
 }
+
+/// macOS/Linux 上 Tauri 从 Finder 启动时 PATH 很短（只有 /usr/bin:/bin:/usr/sbin:/sbin），
+/// 需要补充 Node.js / npm 常见安装路径，否则 check_node / npm_command 找不到命令
+#[cfg(not(target_os = "windows"))]
+pub fn enhanced_path() -> String {
+    let current = std::env::var("PATH").unwrap_or_default();
+    let home = dirs::home_dir().unwrap_or_default();
+    let extra: Vec<String> = vec![
+        "/usr/local/bin".into(),
+        "/opt/homebrew/bin".into(),
+        format!("{}/.nvm/current/bin", home.display()),
+        format!("{}/.volta/bin", home.display()),
+        format!("{}/.nodenv/shims", home.display()),
+        format!("{}/.fnm/current/bin", home.display()),
+        format!("{}/n/bin", home.display()),
+    ];
+    let mut parts: Vec<&str> = extra.iter().map(|s| s.as_str()).collect();
+    if !current.is_empty() {
+        parts.push(&current);
+    }
+    parts.join(":")
+}