style: apply cargo fmt across entire Rust codebase

- Remove Rust formatting check from CI workflow since formatting is now applied
- Standardize import ordering and organization throughout codebase
- Fix indentation, spacing, and line breaks for consistency
- Clean up trailing whitespace and formatting inconsistencies
- Apply rustfmt to all Rust source files including checkpoint, sandbox, commands, and test modules

This establishes a consistent code style baseline for the project.

src-tauri/tests/sandbox/mod.rs

@@ -1,5 +1,5 @@
 //! Comprehensive test suite for sandbox functionality
-//! 
+//!
 //! This test suite validates the sandboxing capabilities across different platforms,
 //! ensuring that security policies are correctly enforced.
 
@@ -14,4 +14,4 @@ pub mod unit;
 pub mod integration;
 
 #[cfg(unix)]
-pub mod e2e; 
+pub mod e2e;