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/sprintf-js/gruntfile.js

@@ -0,0 +1,36 @@
+module.exports = function(grunt) {
+    grunt.initConfig({
+        pkg: grunt.file.readJSON("package.json"),
+
+        uglify: {
+            options: {
+                banner: "/*! <%= pkg.name %> | <%= pkg.author %> | <%= pkg.license %> */\n",
+                sourceMap: true
+            },
+            build: {
+                files: [
+                    {
+                        src: "src/sprintf.js",
+                        dest: "dist/sprintf.min.js"
+                    },
+                    {
+                        src: "src/angular-sprintf.js",
+                        dest: "dist/angular-sprintf.min.js"
+                    }
+                ]
+            }
+        },
+
+        watch: {
+            js: {
+                files: "src/*.js",
+                tasks: ["uglify"]
+            }
+        }
+    })
+
+    grunt.loadNpmTasks("grunt-contrib-uglify")
+    grunt.loadNpmTasks("grunt-contrib-watch")
+
+    grunt.registerTask("default", ["uglify", "watch"])
+}