Add MiniMax Code agent integration

[hetaoBackend]

Summary

• add an API-key-based mcode agent using mcode exec stream JSON
• isolate MiniMax provider state in a per-run mode-0700 MINIMAX_DATA_DIR and clean it up on exit
• add the API-key allowlist, CLI updater mapping, pinned container fallback, trace parser, tests, and setup documentation

Validation

• python3 -m unittest discover -s src/trace_parsing -p "test_*.py" -v
• python3 -m py_compile src/trace_parsing/*.py
• bash -n agents/mcode/solve.sh src/utils/update_agent_cli.sh
• python3 -m json.tool agents/mcode/api_keys.json
• git diff --check
• parsed a real MCode 0.1.2 stream-json trace containing a terminal tool call and successful exec.result
• verified @minimax-ai/code@0.1.2 supports the container Node 22 line
• verified the updater resolves the installed mcode binary and records version 0.1.2

Not run

A full Apptainer plus H100 benchmark job was not available in this environment.