Add is_watch_enabled method to VFS and enhance prefetch cache tests

- Introduced `is_watch_enabled` method to check the status of automatic file watching in the VFS.
- Added a new test for prefetch cache to validate metadata retrieval and error handling for walked roots and external paths.
- Updated the `watch` method in `StdBackend` for cleaner logic.
- Enhanced the `dir_init` field in `PrefetchCache` to store resolved init-file information for directories, improving prefetch operations.

src/lib.rs

@@ -39,6 +39,6 @@ pub use snapshot::{
     InstanceContext, InstanceMetadata, InstanceSnapshot, InstanceWithMeta, InstanceWithMetaMut,
     RojoDescendants, RojoTree,
 };
-pub use snapshot_middleware::{snapshot_from_vfs, Middleware, ScriptType};
+pub use snapshot_middleware::{snapshot_from_vfs, Middleware, ScriptType, INIT_FILE_PRIORITY};
 pub use syncback::{syncback_loop, FsSnapshot, SyncbackData, SyncbackResult, SyncbackSnapshot};
 pub use web::interface as web_api;

src/serve_session.rs

@@ -349,9 +349,10 @@ impl ServeSession {
 
         let snap_start = Instant::now();
         log::trace!("Generating snapshot of instances from VFS");
+        let was_watch_enabled = vfs.is_watch_enabled();
         vfs.set_watch_enabled(false);
         let snapshot = snapshot_from_vfs(&instance_context, vfs, start_path)?;
-        vfs.set_watch_enabled(true);
+        vfs.set_watch_enabled(was_watch_enabled);
         log::debug!("Snapshot built in {:.1?}", snap_start.elapsed());
 
         vfs.clear_prefetch_cache();

src/snapshot_middleware/mod.rs

@@ -544,6 +544,12 @@ mod test {
                 "DEFAULT_PROJECT_NAMES entry {project_name:?} missing from INIT_FILE_PRIORITY"
             );
         }
+        for &name in &priority_names {
+            assert!(
+                DEFAULT_PROJECT_NAMES.contains(&name),
+                "INIT_FILE_PRIORITY has Project entry {name:?} not in DEFAULT_PROJECT_NAMES"
+            );
+        }
     }
 
     #[test]