refactor: replace CommandChildGuard with CommandChild and simplify related methods

src-tauri/src/process/guard.rs

@@ -1,30 +0,0 @@
-use tauri_plugin_shell::process::CommandChild;
-
-#[derive(Debug)]
-pub struct CommandChildGuard(Option<CommandChild>);
-
-impl Drop for CommandChildGuard {
-    #[inline]
-    fn drop(&mut self) {
-        self.kill();
-    }
-}
-
-impl CommandChildGuard {
-    #[inline]
-    pub const fn new(child: CommandChild) -> Self {
-        Self(Some(child))
-    }
-
-    #[inline]
-    pub fn kill(&mut self) {
-        if let Some(child) = self.0.take() {
-            let _ = child.kill();
-        }
-    }
-
-    #[inline]
-    pub fn pid(&self) -> Option<u32> {
-        self.0.as_ref().map(|c| c.pid())
-    }
-}

src-tauri/src/process/mod.rs

@@ -1,4 +1,2 @@
 mod async_handler;
 pub use async_handler::AsyncHandler;
-mod guard;
-pub use guard::CommandChildGuard;