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/write-file-atomic/CHANGELOG.md

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+# 3.0.0
+
+* Implement options.tmpfileCreated callback.
+* Drop Node.js 6, modernize code, return Promise from async function.
+* Support write TypedArray's like in node fs.writeFile.
+* Remove graceful-fs dependency.
+
+# 2.4.3
+
+* Ignore errors raised by `fs.closeSync` when cleaning up after a write
+  error.
+
+# 2.4.2
+
+* A pair of patches to fix some fd leaks.  We would leak fds with sync use
+  when errors occured and with async use any time fsync was not in use. (#34)
+
+# 2.4.1
+
+* Fix a bug where `signal-exit` instances would be leaked. This was fixed when addressing #35.
+
+# 2.4.0
+
+## Features
+
+* Allow chown and mode options to be set to false to disable the defaulting behavior. (#20)
+* Support passing encoding strings in options slot for compat with Node.js API. (#31)
+* Add support for running inside of worker threads (#37)
+
+## Fixes
+
+* Remove unneeded call when returning success (#36)