fix(files): harden drag-and-drop uploads

Co-authored-by: Serhii Dziupin <serkraser@gmail.com>

Co-authored-by: Alan Chen <2144783+alanzchen@users.noreply.github.com>

packages/ui/src/lib/fileContentInvalidation.ts

@@ -0,0 +1,25 @@
+type FileContentInvalidation = {
+  runtimeKey: string;
+  paths: readonly string[];
+};
+
+type FileContentInvalidationListener = (invalidation: FileContentInvalidation) => void;
+
+const listeners = new Set<FileContentInvalidationListener>();
+
+export const notifyFileContentInvalidated = (invalidation: FileContentInvalidation): void => {
+  const runtimeKey = invalidation.runtimeKey.trim();
+  const paths = Array.from(new Set(invalidation.paths.map((path) => path.trim()).filter(Boolean)));
+  if (!runtimeKey || paths.length === 0) return;
+
+  for (const listener of listeners) {
+    listener({ runtimeKey, paths });
+  }
+};
+
+export const subscribeToFileContentInvalidation = (
+  listener: FileContentInvalidationListener,
+): (() => void) => {
+  listeners.add(listener);
+  return () => listeners.delete(listener);
+};