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/schema-utils/declarations/index.d.ts

@@ -0,0 +1,17 @@
+export type Schema = import("./validate").Schema;
+export type JSONSchema4 = import("./validate").JSONSchema4;
+export type JSONSchema6 = import("./validate").JSONSchema6;
+export type JSONSchema7 = import("./validate").JSONSchema7;
+export type ExtendedSchema = import("./validate").ExtendedSchema;
+import { validate } from "./validate";
+import { ValidationError } from "./validate";
+import { enableValidation } from "./validate";
+import { disableValidation } from "./validate";
+import { needValidate } from "./validate";
+export {
+  validate,
+  ValidationError,
+  enableValidation,
+  disableValidation,
+  needValidate,
+};