[codex] add tqqq hybrid overlay research follow-ups

[Pigbibi]

What changed

• add four research-only backtest scripts around the hybrid_growth_income / TQQQ attack sleeve
• add focused tests for each research script
• export comparison CSV / summary markdown / recommendation json for each round

Why

This series answers a narrow question without touching runtime logic:

• do extra daily indicator gates improve the TQQQ sleeve without obvious overfitting?
• when the TQQQ sleeve is out, is CASH, BOXX, or QQQ the better place to sit?
• does a minimal throttle or in-position scaling create a smoother path without giving up too much CAGR?

Impact

• no runtime behavior changes
• no Cloud Run / paper config changes
• adds research artifacts that document what was tested and why the current baseline should stay unchanged

Validation

• python3 -m py_compile research/backtest_hybrid_growth_indicator_variants.py research/backtest_hybrid_growth_idle_throttle_followup.py research/backtest_hybrid_growth_position_scaling_followup.py research/backtest_hybrid_growth_continuous_scaling_followup.py tests/test_hybrid_growth_indicator_variants.py tests/test_hybrid_growth_idle_throttle_followup.py tests/test_hybrid_growth_position_scaling_followup.py tests/test_hybrid_growth_continuous_scaling_followup.py
• PYTHONPATH=/private/tmp/qsl-ibkr-tqqq-research:/Users/lisiyi/Projects/UsEquityStrategies:/Users/lisiyi/Projects/UsEquityStrategies/src:/Users/lisiyi/Projects/QuantPlatformKit/src /Users/lisiyi/Projects/InteractiveBrokersPlatform/.venv/bin/python -m pytest tests/test_hybrid_growth_indicator_variants.py tests/test_hybrid_growth_idle_throttle_followup.py tests/test_hybrid_growth_position_scaling_followup.py tests/test_hybrid_growth_continuous_scaling_followup.py