GHSA-qf73-2hrx-xprp: PraisonAI has sandbox escape via exception frame traversal in `execute_code` (subprocess mode)

PraisonAI's `execute_code()` function has a critical sandbox escape vulnerability in its subprocess mode. The subprocess uses a blocklist of only 11 forbidden attributes, missing four key attributes (`__traceback__`, `tb_frame`, `f_back`, `f_builtins`) that attackers can chain together through exception handling to access the real Python builtins and execute arbitrary code, completely bypassing the sandbox.