windows: Fix FS-related issues (#23369)

I've noticed an occasional error: `ignoring event C:\some\path\to\file
outside of root path \\?\C:\some\path`. This happens because UNC paths
always fail to match with non-UNC paths during operations like
`strip_prefix` or `starts_with`. To address this, I changed the types of
some key parameters to `SanitizedPath`. With this adjustment, FS events
are now correctly identified, and under the changes in this PR, the
`test_rescan_and_remote_updates` test also passes successfully on
Windows.

Release Notes:

- N/A

crates/fs/src/fs_watcher.rs

@@ -1,7 +1,7 @@
 use notify::EventKind;
 use parking_lot::Mutex;
 use std::sync::{Arc, OnceLock};
-use util::ResultExt;
+use util::{paths::SanitizedPath, ResultExt};
 
 use crate::{PathEvent, PathEventKind, Watcher};
 
@@ -24,7 +24,7 @@ impl FsWatcher {
 
 impl Watcher for FsWatcher {
     fn add(&self, path: &std::path::Path) -> gpui::Result<()> {
-        let root_path = path.to_path_buf();
+        let root_path = SanitizedPath::from(path);
 
         let tx = self.tx.clone();
         let pending_paths = self.pending_path_events.clone();
@@ -44,8 +44,9 @@ impl Watcher for FsWatcher {
                         .paths
                         .iter()
                         .filter_map(|event_path| {
+                            let event_path = SanitizedPath::from(event_path);
                             event_path.starts_with(&root_path).then(|| PathEvent {
-                                path: event_path.clone(),
+                                path: event_path.as_path().to_path_buf(),
                                 kind,
                             })
                         })