fix: resolve import errors in test modules and remove unused variables

Co-authored-by: aider (openai/andrew/openrouter/anthropic/claude-sonnet-4) <aider@aider.chat>

src/tests/modes/save_tests.rs

@@ -31,7 +31,7 @@ mod tests {
         
         // Create an empty test file
         {
-            let file = File::create(&file_path).expect("Failed to create empty test file");
+            let _file = File::create(&file_path).expect("Failed to create empty test file");
             // File is automatically closed when it goes out of scope
         }