Add support for prefix-based filtering in addition to suffix filtering

[JANguaishen]

Thank you for providing such a great tool. While using FileMonitor, I noticed that it currently supports suffix-based filtering to exclude or include specific files or processes based on their path suffixes. However, in my use case, I often need to monitor only a specific directory or subdirectories, such as /Users/username/path.

Unfortunately, suffix filtering alone does not allow this kind of filtering efficiently. It would be extremely helpful if FileMonitor could also support prefix-based filtering, allowing users to specify a directory path as the prefix to include or exclude monitored events.