Port forward to ts-rs 8.1 (currently: git only; waiting for 8.1.1+) (#2443)

Port forward to ts-rs 8.1

We're just waiting on a release that includes a PR that we sent[1] for this
to use the cargo version. For now we'll have to use the git release.

[1]: c5109a00e4

src/lib/routeLoaders.ts

@@ -39,7 +39,9 @@ export const settingsLoader: LoaderFunction = async ({
     )
     if (projectPathData) {
       const { project_path } = projectPathData
-      const { settings: s } = await loadAndValidateSettings(project_path)
+      const { settings: s } = await loadAndValidateSettings(
+        project_path || undefined
+      )
       settings = s
     }
   }
@@ -118,6 +120,7 @@ export const fileLoader: LoaderFunction = async ({
             children: [],
             kcl_file_count: 0,
             directory_count: 0,
+            metadata: null,
             default_file: project_path,
           },
       file: {