fix(runtime): preserve schedule phase across worker restarts

[pjy008008]

What changed

• Anchor schedule.tradingDayIndex to the bot's EvaluationWindow.eligibleFrom date.
• Count regular NYSE sessions from that fixed date, skipping weekends and standard exchange holidays.
• Reconstruct the same index after a worker restart, then increment only across newly observed date ranges.
• Add the launch-readiness regression test tradingDayIndexSurvivesARestart across Thanksgiving.

Why

The live Basic runtime previously incremented tradingDayIndex only in memory. Restarting a trading worker reset the next observed session to day 1, shifting EVERY_N_TRADING_DAYS execution compared with the backtest schedule.

This implements launch-readiness §3.1 using the selected rule: the first regular market session on or after executionEligibleFrom is day 1.

Impact

Worker restarts no longer change the phase of trading-day schedules. Existing intraday candle, session-close, week, and month signals keep their current behavior.

Validation

• ./gradlew.bat :apps:trading-worker:test --tests com.idea2strategy.trading.worker.runtime.BasicMarketSignalStateTest --no-daemon --console=plain
• ./gradlew.bat check --no-daemon --build-cache --parallel --console=plain
• powershell -NoProfile -ExecutionPolicy Bypass -File ./scripts/test-github-action-pins.ps1