Initial commit: Developer Tools MVP with visual editor

- Complete React app with 7 developer tools
- JSON Tool with visual structured editor
- Serialize Tool with visual structured editor
- URL, Base64, CSV/JSON, Beautifier, Diff tools
- Responsive navigation with dropdown menu
- Dark/light mode toggle
- Mobile-responsive design with sticky header
- All tools working with copy/paste functionality

node_modules/fork-ts-checker-webpack-plugin/lib/reporter/FilesChange.d.ts

@@ -0,0 +1,16 @@
+import { Compiler } from 'webpack';
+interface FilesChange {
+    changedFiles?: string[];
+    deletedFiles?: string[];
+}
+declare function getFilesChange(compiler: Compiler): FilesChange;
+declare function updateFilesChange(compiler: Compiler, change: FilesChange): void;
+declare function clearFilesChange(compiler: Compiler): void;
+/**
+ * Computes aggregated files change based on the subsequent files changes.
+ *
+ * @param changes List of subsequent files changes
+ * @returns Files change that represents all subsequent changes as a one event
+ */
+declare function aggregateFilesChanges(changes: FilesChange[]): FilesChange;
+export { FilesChange, getFilesChange, updateFilesChange, clearFilesChange, aggregateFilesChanges };