Refine strategy switch layout and DCA naming

[Pigbibi]

Summary

• group strategy switch controls into runtime, income layer, and reserved cash sections
• keep related dropdowns and numeric inputs aligned in two-column rows
• rename Nasdaq/S&P 500 Smart DCA to Nasdaq 100 / S&P 500 Smart DCA with Chinese label 纳指100 / 标普500 智能定投
• sync embedded page/profile assets

Tests

• node --input-type=module --check < web/strategy-switch-console/worker.js
• inline index.html script node --check
• python3 -m json.tool web/strategy-switch-console/strategy-profiles.example.json >/dev/null
• node --experimental-default-type=module tests/strategy_switch_worker_validation.mjs
• /tmp/qsl-followup-pytest-venv-20260619/bin/python -m pytest tests/test_runtime_settings.py -q