Added execution context management interface and improved CRUD methods

• Introduced TeqFw_Core_Shared_Api_Repo_Context interface for managing execution context repositories with CRUD
  operations.
• Added TeqFw_Core_Shared_Api_Store_Memory for handling in-memory data with key-value storage.
• Enhanced TeqFw_Core_Shared_Api_Model with improved CRUD methods and better parameter handling.
• Added dateISO utility method in TeqFw_Core_Shared_Util_Cast for converting dates to ISO strings.
• Improved documentation across interfaces, including better JSDoc annotations for clarity.
• Refined DTO creation methods with lightweight and entity-specific options.
• Fixed inconsistencies in method return types and improved API stability.
• Expanded test coverage to validate new interfaces and utilities.