feat(server): exclude syncthing folders from external libraries (#24240)

* Add SyncThing folders to External library exclusion

SyncThing is a popular library for syncing files (like pictures) between systems. It can really mess up your library if an external library, which is also used by SyncThing, is added and these folders are not excluded.

* Plural

* fix formatting

---------

Co-authored-by: Jonathan Jogenfors <jonathan@jogenfors.se>

server/src/services/library.service.ts

@@ -223,7 +223,14 @@ export class LibraryService extends BaseService {
       ownerId: dto.ownerId,
       name: dto.name ?? 'New External Library',
       importPaths: dto.importPaths ?? [],
-      exclusionPatterns: dto.exclusionPatterns ?? ['**/@eaDir/**', '**/._*', '**/#recycle/**', '**/#snapshot/**'],
+      exclusionPatterns: dto.exclusionPatterns ?? [
+        '**/@eaDir/**',
+        '**/._*',
+        '**/#recycle/**',
+        '**/#snapshot/**',
+        '**/.stversions/**',
+        '**/.stfolder/**',
+      ],
     });
     return mapLibrary(library);
   }