* Fix callback clearing in workflow execution
The method ClearCompletionCallbacks in the ActivityExecutionContext was modifying the collection during enumeration, which can lead to issues. Converting to a List before removal ensures safe modification without side effects.
* Add log message sanitization for PostgreSQL
The new LogStringExtensions class provides methods to sanitize log messages, ensuring that null characters are replaced with "\0". These changes prevent issues with PostgreSQL's inability to store null characters in strings, improving log data compatibility with the database.
* Rename and update log extension class
Refactor LogStringExtensions to LogExtensions and update summary comment for clarity. This change emphasizes the broader application of the extension methods beyond string manipulation, focusing on sanitizing log messages.
