Enhance path handling and test coverage for mentions

- Improved the extraction logic in `extractFilePath` to handle special cases for escaped spaces and Windows-style paths.
- Updated test cases to cover various scenarios, including paths with consecutive escaped spaces, international characters, and adjacent mentions.
- Refactored mock implementations in tests for better clarity and consistency, ensuring proper handling of asynchronous operations.
- Enhanced error handling for invalid paths and permission issues, providing clearer feedback in test results.

Author: Yikai-Liao