feat(sandbox): boxlite implementation

Author: liyuan

pyproject.toml

@@ -65,6 +65,7 @@ dependencies = [
   "playwright>=1.40.0",
   "beartype>=0.18.5",
   "matplotlib>=3.5.0",
+  "boxlite>=0.6.0",
 ]
 
 [project.optional-dependencies]

src/xagent/sandbox/base.py

@@ -108,6 +108,9 @@ class ExecResult:
     stderr: str
     """Standard error output."""
 
+    error_message: Optional[str] = None
+    """Error message."""
+
     @property
     def success(self) -> bool:
         return self.exit_code == 0