claude refactorings, flutter best practices, platform dependent changes, general cleanup

lib/utils/cache_invalidation_bus.dart

@@ -0,0 +1,20 @@
+import 'dart:async';
+
+/// App-wide pub/sub channel for cache invalidations. Producers (e.g. webdav
+/// move/delete handlers) call [notifyListFiles] after they have dropped the
+/// cached listing for a folder so that any [_FilesView] currently sitting on
+/// that folder — possibly in the background, beneath a child route — can
+/// refresh itself instead of showing the stale snapshot it loaded earlier.
+class CacheInvalidationBus {
+  CacheInvalidationBus._();
+
+  static final StreamController<String> _listFiles = StreamController<String>.broadcast();
+
+  /// Emits the invalidated `pathString` (in `FilesBloc` format: relative,
+  /// no leading or trailing slash; root is '/').
+  static Stream<String> get listFilesStream => _listFiles.stream;
+
+  static void notifyListFiles(String pathString) {
+    _listFiles.add(pathString);
+  }
+}