Avoid crash when new directory created in project root (#8199)

While working on #8158, I noticed a crash when the `data` directory is created at the project root. Turns out it is the issue in the `ydoc-server`, which thinks every filesystem event is about files. Unfortunately, we don‘t have the needed info available, so we need to make the `file/info` request.

app/gui2/ydoc-server/languageServerSession.ts

@@ -70,13 +70,18 @@ export class LanguageServerSession extends ObservableV2<Events> {
       }
     })
 
-    this.ls.on('file/event', (event) => {
+    this.ls.on('file/event', async (event) => {
       if (DEBUG_LOG_SYNC) {
         console.log('file/event', event)
       }
       switch (event.kind) {
         case 'Added':
-          this.getModuleModel(event.path).open()
+          if (isSourceFile(event.path)) {
+            const fileInfo = await this.ls.fileInfo(event.path)
+            if (fileInfo.attributes.kind.type == 'File') {
+              this.getModuleModel(event.path).open()
+            }
+          }
           break
         case 'Modified':
           this.getModuleModelIfExists(event.path)?.reload()
@@ -180,6 +185,10 @@ export class LanguageServerSession extends ObservableV2<Events> {
   }
 }
 
+const isSourceFile = (path: Path): boolean => {
+  return path.segments[0] === 'src' && path.segments[path.segments.length - 1].endsWith('.enso')
+}
+
 const pathToModuleName = (path: Path): string => {
   if (path.segments[0] === 'src') {
     return path.segments.slice(1).join('/')