Rather than computing a diff after processing a batch of FSEvents, we instead detect renames as we're inserting entries. We store an entry_id on the File object that is owned by each buffer, and use this to detect when the path of the File has changed.

We now also manage all File-related state and event emission for Buffers in the LocalWorktree, since the logic will need to be totally different in the remote case.

Co-Authored-By: Max Brunsfeld <maxbrunsfeld@gmail.com>
Co-Authored-By: Antonio Scandurra <me@as-cii.com>