Use entry_id on File instead of worktree::Diff to detect when buffers' files change

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>

zed/src/worktree/fuzzy.rs

@@ -618,6 +618,7 @@ mod tests {
                 abs_path: PathBuf::new().into(),
                 ignores: Default::default(),
                 entries: Default::default(),
+                paths_by_id: Default::default(),
                 removed_entry_ids: Default::default(),
                 root_name: Default::default(),
                 root_char_bag: Default::default(),