#335 Reflexive Loop: Add raw code execution tool (tools.code.exec)

Issue #331 reflexive_loop implementation is broken: PROBLEM: - agent.py:177 passes code='...' to tools.python.run - But python_task.py expects function_name='module.function' not raw code - The LLM-generated code is NEVER actually executed - Verification always returns null (no error = success) SOLUTION: 1. Create tools.code.exec that safely executes raw Python code 2. Run in subprocess with timeout for safety 3. Return stdout, stderr, exit_code 4. Add logging of generated code for debugging ALSO NEEDED: - Checkpoint between turns for crash recovery - Visibility into generated code (currently encrypted) Related: #331