Publish IBKR QQQ/TQQQ research follow-ups

[Pigbibi]

Summary

• add two research-only follow-up backtests for the video QQQ/TQQQ line
• publish comparison tables, recommendation JSON, and markdown summaries for both studies
• register the new retained research artifacts in research/README.md

Verification

• ./.venv/bin/python -m py_compile research/backtest_video_qqq_tqqq_growth_optimizations.py research/backtest_video_qqq_tqqq_position_scaling.py

Notes

• position scaling smooths drawdown but is not a clear upgrade over the retained baseline
• moderate risk-on QQQ -> TQQQ shifts are the cleanest growth lever in this study