feat: major update - Markdown Editor, CodeMirror upgrades, SEO improvements, tool cleanup

- Added new Markdown Editor with live preview, GFM support, PDF/HTML/DOCX export
- Upgraded all paste fields to CodeMirror with syntax highlighting and expand/collapse
- Enhanced Object Editor with advanced URL fetching and preview mode
- Improved export views with syntax highlighting in Table/Object editors
- Implemented SEO improvements (FAQ schema, breadcrumbs, internal linking)
- Added Related Tools recommendations component
- Created custom 404 page with tool suggestions
- Consolidated tools: removed JSON, Serialize, CSV-JSON (merged into main editors)
- Updated documentation and cleaned up redundant files
- Updated release notes with user-centric improvements

src/components/Layout.js

@@ -57,7 +57,7 @@ const Layout = ({ children }) => {
       
       {/* Header */}
       <header className="fixed top-0 left-0 right-0 z-50 bg-white/80 dark:bg-slate-800/80 backdrop-blur-md shadow-lg border-b border-slate-200/50 dark:border-slate-700/50 flex-shrink-0">
-        <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8">
+        <div className={isToolPage ? "px-4 sm:px-6 lg:px-8" : "max-w-7xl mx-auto px-4 sm:px-6 lg:px-8"}>
           <div className="flex justify-between items-center h-16">
             <button onClick={() => navigateWithGuard('/')} className="flex items-center group">
               <div className="relative">
@@ -250,16 +250,16 @@ const Layout = ({ children }) => {
       )}
 
       {/* Main Content */}
-      <div className="flex flex-1 pt-16">
+      <div className="flex flex-1 pt-16 min-w-0 w-full max-w-full overflow-x-hidden">
         {/* Main Content Area */}
-        <main className="flex-1 flex flex-col">
+        <main className="flex-1 flex flex-col min-w-0 w-full max-w-full">
           {isToolPage && !isInvoicePreviewPage ? (
             <div className="block">
               <div className="hidden lg:block fixed top-16 left-0 z-[9999]">
                 <ToolSidebar navigateWithGuard={navigateWithGuard} />
               </div>
-              <div className="flex-1 flex flex-col min-h-0 pl-0 lg:pl-16">
-                <div className="flex-1 p-4 sm:p-6 w-full min-w-0 overflow-auto">
+              <div className="flex-1 flex flex-col pl-0 lg:pl-16 min-w-0">
+                <div className="p-4 sm:p-6 w-full min-w-0 max-w-full overflow-x-hidden">
                   {children}
                 </div>
               </div>