fix(windows): wrap npx/npm commands with cmd /c for MCP export

On Windows, npx, npm, yarn, pnpm, node, bun, and deno are actually
.cmd batch files that require cmd /c wrapper to execute properly.
This fixes the Claude Code /doctor warning:
"Windows requires 'cmd /c' wrapper to execute npx"

The transformation is applied when exporting MCP config to ~/.claude.json:
- Before: {"command": "npx", "args": ["-y", "foo"]}
- After:  {"command": "cmd", "args": ["/c", "npx", "-y", "foo"]}

Uses conditional compilation (#[cfg(windows)]) for zero overhead on
other platforms.

Closes #453

src-tauri/src/claude_mcp.rs

@@ -7,6 +7,64 @@ use std::path::{Path, PathBuf};
 use crate::config::{atomic_write, get_claude_mcp_path, get_default_claude_mcp_path};
 use crate::error::AppError;
 
+/// 需要在 Windows 上用 cmd /c 包装的命令
+/// 这些命令在 Windows 上实际是 .cmd 批处理文件，需要通过 cmd /c 来执行
+#[cfg(windows)]
+const WINDOWS_WRAP_COMMANDS: &[&str] = &["npx", "npm", "yarn", "pnpm", "node", "bun", "deno"];
+
+/// Windows 平台：将 `npx args...` 转换为 `cmd /c npx args...`
+/// 解决 Claude Code /doctor 报告的 "Windows requires 'cmd /c' wrapper to execute npx" 警告
+#[cfg(windows)]
+fn wrap_command_for_windows(obj: &mut Map<String, Value>) {
+    // 只处理 stdio 类型（默认或显式）
+    let server_type = obj.get("type").and_then(|v| v.as_str()).unwrap_or("stdio");
+    if server_type != "stdio" {
+        return;
+    }
+
+    let Some(cmd) = obj.get("command").and_then(|v| v.as_str()) else {
+        return;
+    };
+
+    // 已经是 cmd 的不重复包装
+    if cmd.eq_ignore_ascii_case("cmd") || cmd.eq_ignore_ascii_case("cmd.exe") {
+        return;
+    }
+
+    // 提取命令名（去掉 .cmd 后缀和路径）
+    let cmd_name = Path::new(cmd)
+        .file_stem()
+        .and_then(|s| s.to_str())
+        .unwrap_or(cmd);
+
+    let needs_wrap = WINDOWS_WRAP_COMMANDS
+        .iter()
+        .any(|&c| cmd_name.eq_ignore_ascii_case(c));
+
+    if !needs_wrap {
+        return;
+    }
+
+    // 构建新的 args: ["/c", "原命令", ...原args]
+    let original_args = obj
+        .get("args")
+        .and_then(|v| v.as_array())
+        .cloned()
+        .unwrap_or_default();
+
+    let mut new_args = vec![Value::String("/c".into()), Value::String(cmd.into())];
+    new_args.extend(original_args);
+
+    obj.insert("command".into(), Value::String("cmd".into()));
+    obj.insert("args".into(), Value::Array(new_args));
+}
+
+/// 非 Windows 平台无需处理
+#[cfg(not(windows))]
+fn wrap_command_for_windows(_obj: &mut Map<String, Value>) {
+    // 非 Windows 平台不做任何处理
+}
+
 #[derive(Debug, Clone, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub struct McpStatus {
@@ -339,6 +397,9 @@ pub fn set_mcp_servers_map(
         obj.remove("homepage");
         obj.remove("docs");
 
+        // Windows 平台自动包装 npx/npm 等命令为 cmd /c 格式
+        wrap_command_for_windows(&mut obj);
+
         out.insert(id.clone(), Value::Object(obj));
     }
 
@@ -352,3 +413,136 @@ pub fn set_mcp_servers_map(
     write_json_value(&path, &root)?;
     Ok(())
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use serde_json::json;
+
+    /// 测试 Windows 命令包装功能
+    /// 由于使用条件编译，在非 Windows 平台上测试的是空函数
+    #[test]
+    fn test_wrap_command_for_windows_npx() {
+        let mut obj = json!({"command": "npx", "args": ["-y", "@upstash/context7-mcp"]})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        #[cfg(windows)]
+        {
+            assert_eq!(obj["command"], "cmd");
+            assert_eq!(
+                obj["args"],
+                json!(["/c", "npx", "-y", "@upstash/context7-mcp"])
+            );
+        }
+
+        #[cfg(not(windows))]
+        {
+            // 非 Windows 平台不做任何处理
+            assert_eq!(obj["command"], "npx");
+        }
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_npm() {
+        let mut obj = json!({"command": "npm", "args": ["run", "start"]})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        #[cfg(windows)]
+        {
+            assert_eq!(obj["command"], "cmd");
+            assert_eq!(obj["args"], json!(["/c", "npm", "run", "start"]));
+        }
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_already_cmd() {
+        // 已经是 cmd 的不应该重复包装
+        let mut obj = json!({"command": "cmd", "args": ["/c", "npx", "-y", "foo"]})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        assert_eq!(obj["command"], "cmd");
+        // args 应该保持不变，不会变成 ["/c", "cmd", "/c", "npx", ...]
+        assert_eq!(obj["args"], json!(["/c", "npx", "-y", "foo"]));
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_http_type_skipped() {
+        // http 类型不应该被处理
+        let mut obj = json!({"type": "http", "url": "https://example.com/mcp"})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        assert!(!obj.contains_key("command"));
+        assert_eq!(obj["url"], "https://example.com/mcp");
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_other_command_skipped() {
+        // 非目标命令（如 python）不应该被包装
+        let mut obj = json!({"command": "python", "args": ["server.py"]})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        // python 不在 WINDOWS_WRAP_COMMANDS 列表中，不应该被包装
+        assert_eq!(obj["command"], "python");
+        assert_eq!(obj["args"], json!(["server.py"]));
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_no_args() {
+        // 没有 args 的情况
+        let mut obj = json!({"command": "npx"}).as_object().unwrap().clone();
+        wrap_command_for_windows(&mut obj);
+
+        #[cfg(windows)]
+        {
+            assert_eq!(obj["command"], "cmd");
+            assert_eq!(obj["args"], json!(["/c", "npx"]));
+        }
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_with_cmd_suffix() {
+        // 处理 npx.cmd 格式
+        let mut obj = json!({"command": "npx.cmd", "args": ["-y", "foo"]})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        #[cfg(windows)]
+        {
+            assert_eq!(obj["command"], "cmd");
+            assert_eq!(obj["args"], json!(["/c", "npx.cmd", "-y", "foo"]));
+        }
+    }
+
+    #[test]
+    fn test_wrap_command_for_windows_case_insensitive() {
+        // 大小写不敏感
+        let mut obj = json!({"command": "NPX", "args": ["-y", "foo"]})
+            .as_object()
+            .unwrap()
+            .clone();
+        wrap_command_for_windows(&mut obj);
+
+        #[cfg(windows)]
+        {
+            assert_eq!(obj["command"], "cmd");
+            assert_eq!(obj["args"], json!(["/c", "NPX", "-y", "foo"]));
+        }
+    }
+}