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/ajv/lib/dot/multipleOf.jst

@@ -0,0 +1,22 @@
+{{# def.definitions }}
+{{# def.errors }}
+{{# def.setupKeyword }}
+{{# def.$data }}
+
+{{# def.numberKeyword }}
+
+var division{{=$lvl}};
+if ({{?$isData}}
+      {{=$schemaValue}} !== undefined && (
+      typeof {{=$schemaValue}} != 'number' ||
+    {{?}}
+      (division{{=$lvl}} = {{=$data}} / {{=$schemaValue}},
+      {{? it.opts.multipleOfPrecision }}
+        Math.abs(Math.round(division{{=$lvl}}) - division{{=$lvl}}) > 1e-{{=it.opts.multipleOfPrecision}}
+      {{??}}
+        division{{=$lvl}} !== parseInt(division{{=$lvl}})
+      {{?}}
+      )
+    {{?$isData}}  )  {{?}} ) {
+  {{# def.error:'multipleOf' }}
+} {{? $breakOnError }} else { {{?}}