Enhance matching module with reference identity and caching improvements

- Introduced a new `RefIdentity` type to store reference details (name and className) in the matching process.
- Updated `VCache` and `SCache` structures to include references, improving the handling of reference comparisons during matching.
- Modified `cacheVirtual` and `cacheStudio` functions to support reference caching, enhancing performance and accuracy in matching.
- Improved `countOwnDiffs` function to account for reference mismatches, ensuring more precise cost calculations.
- Added comprehensive tests to validate the new reference handling and caching mechanisms.

These changes significantly enhance the efficiency and accuracy of the matching process in the application.

src/serve_session.rs

@@ -193,6 +193,7 @@ impl ServeSession {
             Arc::clone(&suppressed_paths),
             Arc::clone(&ref_path_index),
             root_project.folder_location().to_path_buf(),
+            root_project.file_location.clone(),
             critical_error_receiver,
             git_repo_root.clone(),
         );
@@ -366,7 +367,7 @@ impl ServeSession {
     /// Does NOT apply corrections — the tree is left unchanged.
     pub fn check_tree_freshness(&self) -> TreeFreshnessReport {
         let start = Instant::now();
-        let start_path = self.root_project.folder_location();
+        let start_path: &Path = &self.root_project.file_location;
         let instance_context = InstanceContext::new();
 
         let snapshot = match snapshot_from_vfs(&instance_context, &self.vfs, start_path) {
@@ -429,7 +430,7 @@ impl ServeSession {
         }
 
         let start = Instant::now();
-        let start_path = self.root_project.folder_location();
+        let start_path: &Path = &self.root_project.file_location;
         let instance_context = InstanceContext::new();
 
         let snapshot = match snapshot_from_vfs(&instance_context, &self.vfs, start_path) {