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/postcss-custom-properties/dist/lib/options.d.ts

@@ -0,0 +1,26 @@
+export declare type ImportFromSource = {
+    from: string;
+    type?: string;
+} | string;
+export declare type ImportCustomProperties = {
+    customProperties?: Record<string, string>;
+    'custom-properties'?: Record<string, string>;
+};
+export declare type ImportAsFunction = () => ImportFromSource | ImportCustomProperties;
+export declare type ImportAsPromise = Promise<ImportFromSource | ImportCustomProperties>;
+export declare type ImportAsFunctionPromise = () => Promise<ImportFromSource | ImportCustomProperties>;
+export declare type ImportOptions = ImportFromSource | ImportCustomProperties | ImportAsFunction | ImportAsPromise | ImportAsFunctionPromise;
+export declare type ExportJSONFunction = (customProperties?: Record<string, string>) => Record<string, string>;
+export declare type ExportToSource = {
+    to: string;
+    type?: string;
+    toJSON: ExportJSONFunction;
+} | string;
+export declare type ExportCustomProperties = {
+    customProperties?: Record<string, string>;
+    'custom-properties'?: Record<string, string>;
+    toJSON: ExportJSONFunction;
+};
+export declare type ExportAsFunction = (ExportCustomProperties: any) => void;
+export declare type ExportAsFunctionPromise = (ExportCustomProperties: any) => Promise<void>;
+export declare type ExportOptions = ExportToSource | ExportCustomProperties | ExportAsFunction | ExportAsFunctionPromise;