refactor(Rest): Rename private_field module to PascalCase

Rename Source/Fn/Transform/private_field.rs to PrivateField.rs and update the module declaration in mod.rs to follow the project's PascalCase naming convention for modules and files.

This aligns with the CLAUDE.md mandate that all code follows PascalCase naming for functions, variables, parameters, structs, modules, and file names.

Author: NikolaRHristov

Source/Fn/Transform/private_field.rs Source/Fn/Transform/PrivateField.rsSource/Fn/Transform/private_field.rs renamed to Source/Fn/Transform/PrivateField.rs

@@ -4,6 +4,7 @@
 //! - Private field conversion (#field -> __field)
 //! - Additional VSCode-specific transformations
 
-pub mod private_field;
+#[path = "PrivateField.rs"]
+pub mod PrivateField;
 
-pub use private_field::PrivateFieldTransform;
+pub use PrivateField::PrivateFieldTransform;