[WIP] Update logging for trace options configuration

[Copilot]

• Add _backgroundServiceExceptions list to Host.cs to capture background service exceptions
• In TryExecuteBackgroundServiceAsync, capture exceptions with ExceptionDispatchInfo when BackgroundServiceExceptionBehavior.StopHost
• At the end of StopAsync, rethrow captured exceptions (single exception or AggregateException for multiple)
• Add BackgroundServiceExceptionsPropagating event ID to LoggerEventIds.cs
• Add BackgroundServiceExceptionsPropagating log method to HostingLoggerExtensions.cs
• Add tests for exception propagation to existing HostTests.cs
• Build and verify no regressions

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