Was only checking quantity limit and VaR. Now runs all 5 risk checks:
1. Kill switch / circuit breaker (via TradingServiceKillSwitch)
2. Max order size + position limits (via RiskRepository.get_risk_limits)
3. Daily loss / drawdown limit (via RiskRepository.get_risk_metrics)
4. Leverage limit (via config + RiskRepository.get_risk_metrics)
5. VaR limit (via RiskEngine.check_var_limit, existing)
Violations accumulate rather than short-circuit so callers see all
failures at once. Added 6 tests verifying violation type coverage.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>