MaxKB sandbox bypass

MaxKB is an open-source AI assistant for enterprise. Prior to version 2.0.0, the sandbox design rules can be bypassed because MaxKB only restricts the execution permissions of files in a specific directory. Therefore, an attacker can use the `shutil.copy2` method in Python to copy the command they want to execute to the executable directory. This bypasses directory restrictions and reverse shell. Version 2.0.0 fixes the issue.