fix(core): resolve 16 audit findings — race conditions, design flaws, glue code, and performance issues - #529

Possible null reference return.

Possible null reference argument for parameter 'query' in 'Task<HttpResponseDTO<PagedResultDTO<ExtensionDTO>>> IExtensionHttpClient.QueryExtensionsAsync(ExtensionQueryDTO query, CancellationToken cancellationToken = default(CancellationToken))'.

Cannot convert null literal to non-nullable reference type.

Non-nullable field '_fileListener' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_currentLogDate' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

'TextTraceListener.Dispose()' hides inherited member 'TraceListener.Dispose()'. Use the new keyword if hiding was intended.

Cannot convert null literal to non-nullable reference type.

Non-nullable field '_fileListener' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.

Non-nullable field '_currentLogDate' must contain a non-null value when exiting constructor. Consider adding the 'required' modifier or declaring the field as nullable.