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/papaparse/tests/long-sample.csv

@@ -0,0 +1,8 @@
+Grant,Dyer,Donec.elementum@orciluctuset.example,2013-11-23T02:30:31-08:00,2014-05-31T01:06:56-07:00,Magna Ut Associates,ljenkins
+Cherokee,Shields,Nulla.Semper.Tellus@duinec.example,2014-11-22T16:43:51-08:00,2013-09-26T11:47:15-07:00,Pede Corporation,Donec.elementum@orciluctuset.example
+Catherine,Parrish,lorem@feugiatnon.example,2015-02-11T12:01:10-08:00,2015-02-26T00:29:40-08:00,Phasellus Fermentum Convallis PC,Donec.elementum@orciluctuset.example
+Destiny,Shannon,libero@Aenean.example,2015-07-14T09:38:11-07:00,2014-01-11T14:53:04-08:00,Pretium Et Inc.,Donec.elementum@orciluctuset.example
+Callum,Underwood,Phasellus@Quisquetincidunt.example,2013-09-13T18:49:35-07:00,2014-12-04T23:04:19-08:00,Sed Turpis Nec LLP,ljenkins
+Elliott,Wright,cursus@nibh.example,2015-04-20T14:35:19-07:00,2015-03-05T12:56:46-08:00,Dolor Associate,Phasellus@Quisquetincidunt.example
+Galvin,Foley,nisi.Aenean.eget@atauctorullamcorper.example,2014-03-20T23:20:15-07:00,2014-06-11T15:00:23-07:00,Adipiscing Industrie,Phasellus@Quisquetincidunt.example
+Talon,Salinas,posuere.vulputate.lacus@Donecsollicitudin.example,2015-01-31T09:19:02-08:00,2014-12-17T04:59:18-08:00,Aliquam Iaculis Incorporate,Phasellus@Quisquetincidunt.example