fix: resolve all cargo clippy warnings

- Fix toml version requirement metadata warning
- Replace clone() with std::slice::from_ref()
- Collapse nested if statements
- Add #[allow(dead_code)] to test utility functions
- Fix unused imports and variables in tests
- Use unwrap_or_else instead of expect with format!

wtismycode-core/tests/enhanced_analysis.rs

@@ -3,7 +3,6 @@
 //! These tests verify that the enhanced analysis functionality works correctly
 //! with complex code that includes integrations, calls, and docstrings.
 
-use std::fs;
 use std::path::Path;
 use wtismycode_core::{Config, scanner::FileScanner, python_analyzer::PythonAnalyzer};