This commit updates various files across the Core and WebApp projects to replace traditional collection initializers with C# 12 collection expressions. Changes include modifications to EventAssignment.cs, TeamScheduler_DecisionTree.cs, CareerField.cs, EventDefinition.cs, and several components in the WebApp. These updates enhance code readability and maintainability by adhering to modern C# syntax standards.
Enhanced the application's service layer by adding FormValidationService and EventDefinitionService to the dependency injection container in Program.cs. Updated Create, Edit, and other relevant components to utilize these services for improved form validation and event processing functionality.