docs: polish project for portfolio presentation

[bbbbronya]

Summary

• Add a concise findings table and clearer reproduction guidance
• Organize exploratory OpenRouter probes under scripts/probes/
• Remove four obsolete duplicate figures while keeping the eight current outputs
• Add a lightweight GitHub Actions Python syntax check

Validation

• python3 -m compileall -q run_experiment.py analyze_results.py sources scripts
• Confirmed all eight figures generated by the current analysis script are present
• git diff --check