fix(risk): add daily loss NEW_RISK contract

[Pigbibi]

Summary

• add optional daily_loss_usd reconciliation fact and max_daily_loss_usd runtime limit
• fail closed on missing/invalid configured daily-loss facts and prohibit at/above the limit
• omit the daily-loss axis when no limit is configured, preserving backward compatibility

Tests

• PYTHONPATH=src python3 -m pytest tests/test_account_new_risk_gate.py tests/test_risk_gate.py -q (130 passed, 405 subtests passed)
• python3 -m ruff check src/quant_platform_kit/risk/account_new_risk_gate.py src/quant_platform_kit/risk/contracts.py tests/test_account_new_risk_gate.py (passed)
• full suite: 1987 passed, 1 skipped, 1 unrelated time-sensitive failure in test_automatic_codex_decision_rejects_missing_observation_source_before_ai (observation_in_future vs expected observation_source_unavailable)