style: apply cargo fmt to entire codebase

Standardize code formatting across all 173 Rust source files
using rustfmt. No functional changes - purely cosmetic.

This establishes a consistent code style baseline for the
project going forward.

src/application/dtos/mod.rs

@@ -12,4 +12,3 @@ pub mod settings_dto;
 pub mod share_dto;
 pub mod trash_dto;
 pub mod user_dto;
-