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/@webassemblyjs/utf8/test/index.js

@@ -0,0 +1,13 @@
+const { assert } = require("chai");
+
+const { decode, encode } = require("../lib");
+
+describe("UTF8", () => {
+  it("should f-1(f(x)) = x", () => {
+    assert.equal(decode(encode("foo")), "foo");
+    assert.equal(decode(encode("éé")), "éé");
+
+    // TODO(sven): utf8 encoder fails here
+    // assert.equal(decode(encode("🤣见見")), "🤣见見");
+  });
+});