Remove HTML Preview Tool from navigation and add to gitignore

- Removed HTML Preview Tool from navigation menu in Layout.js
- Cleaned up unused Code import
- Added HTML Preview related files to .gitignore
- Project builds successfully without HTML Preview Tool

src/components/Layout.js

@@ -1,6 +1,6 @@
 import React, { useState, useEffect, useRef } from 'react';
 import { Link, useLocation } from 'react-router-dom';
-import { Code2, Home, ChevronDown, Menu, X, Database, FileText, Link as LinkIcon, Hash, FileSpreadsheet, Wand2, GitCompare, Code } from 'lucide-react';
+import { Home, Hash, FileText, Key, Palette, QrCode, FileSpreadsheet, Wand2, GitCompare, Menu, X } from 'lucide-react';
 import ThemeToggle from './ThemeToggle';
 
 const Layout = ({ children }) => {
@@ -41,7 +41,7 @@ const Layout = ({ children }) => {
     { path: '/csv-json', name: 'CSV/JSON Tool', icon: FileSpreadsheet, description: 'Convert CSV ↔ JSON' },
     { path: '/beautifier', name: 'Beautifier Tool', icon: Wand2, description: 'Beautify/minify code' },
     { path: '/diff', name: 'Diff Tool', icon: GitCompare, description: 'Compare text differences' },
-    { path: '/html-preview', name: 'HTML Preview', icon: Code, description: 'Render HTML, CSS, JS' }
+
   ];
 
   return (