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/workbox-webpack-plugin/tsconfig.json

@@ -0,0 +1,14 @@
+{
+  "extends": "../../tsconfig",
+  "compilerOptions": {
+    "esModuleInterop": true,
+    "module": "CommonJS",
+    "outDir": "./build",
+    "resolveJsonModule": true,
+    "rootDir": "./src",
+    "target": "ES2018",
+    "tsBuildInfoFile": "./tsconfig.tsbuildinfo"
+  },
+  "include": ["src/**/*.ts"],
+  "references": [{"path": "../workbox-build/"}]
+}