feature: Add evolution trace logging for RL training support

[totoluo]

Description

Implements evolution trace logging feature as requested in #210. Although it has been closed but I feel this might be helpful at some stage?
This feature enables capturing detailed evolution traces for RL training and analysis.

• Add EvolutionTracer class for real-time trace logging
• Support JSONL, JSON, and HDF5 formats
• Add checkpoint extraction functions for lineage analysis
• Include prompts, LLM responses, and improvement metrics
• Add test suite
• Update configuration to support evolution_trace settings

Changes

• New Files:

  • openevolve/evolution_trace.py - Core tracing functionality
  • openevolve/utils/trace_export_utils.py - Export/import utilities
  • tests/test_evolution_trace.py - Test suite

• Modified Files:

  • openevolve/config.py - Added EvolutionTraceConfig
  • openevolve/controller.py - Initialize tracer
  • openevolve/process_parallel.py - Log traces
  • configs/default_config.yaml - Added default config

Testing

• All 25 tests passing
• Tested with function_minimization example
• Generated example traces successfully

Example Usage

evolution_trace:
  enabled: true
  format: 'jsonl'
  include_code: true
  include_prompts: true
  output_path: 'evolution_trace.jsonl'