[codex] Support TQQQ income env overrides

[Pigbibi]

Summary

• load optional INCOME_THRESHOLD_USD and QQQI_INCOME_RATIO in LongBridge runtime settings
• apply those values as tqqq_growth_income runtime overrides
• sync the income override vars through HK/SG Cloud Run env workflows and document them

Validation

• bash tests/test_sync_cloud_run_env_workflow.sh
• git diff --check
• uv run --with ruff ruff check runtime_config_support.py strategy_runtime.py tests/test_runtime_config_support.py tests/test_strategy_runtime.py
• PYTHONPATH=.:../UsEquityStrategies/src:../QuantPlatformKit/src uv run --with pytest --with pandas --with numpy --with pytz --with requests --with flask --with pandas-market-calendars --with longport python -m unittest tests.test_runtime_config_support tests.test_strategy_runtime -v