feat: Initialize frontend with React, Vite, and Tailwind CSS

- Set up main entry point for React application.
- Create About, Home, NotFound, Privacy, and Terms pages with SEO support.
- Implement API service for file uploads and task management.
- Add global styles using Tailwind CSS.
- Create utility functions for SEO and text processing.
- Configure Vite for development and production builds.
- Set up Nginx configuration for serving frontend and backend.
- Add scripts for cleanup of expired files and sitemap generation.
- Implement deployment script for production environment.

frontend/src/pages/AboutPage.tsx

@@ -0,0 +1,49 @@
+import { useTranslation } from 'react-i18next';
+import { Helmet } from 'react-helmet-async';
+
+export default function AboutPage() {
+  const { t } = useTranslation();
+
+  return (
+    <>
+      <Helmet>
+        <title>{t('common.about')} — {t('common.appName')}</title>
+        <meta name="description" content="About our free online file conversion tools." />
+      </Helmet>
+
+      <div className="prose mx-auto max-w-2xl dark:prose-invert">
+        <h1>{t('common.about')}</h1>
+
+        <p>
+          We provide free, fast, and secure online tools for converting, compressing,
+          and processing files — PDFs, images, videos, and text.
+        </p>
+
+        <h2>Why use our tools?</h2>
+        <ul>
+          <li><strong>100% Free</strong> — No hidden charges, no sign-up required.</li>
+          <li><strong>Private & Secure</strong> — Files are auto-deleted within 2 hours.</li>
+          <li><strong>Fast Processing</strong> — Server-side processing for reliable results.</li>
+          <li><strong>Works Everywhere</strong> — Desktop, tablet, or mobile.</li>
+        </ul>
+
+        <h2>Available Tools</h2>
+        <ul>
+          <li>PDF to Word Converter</li>
+          <li>Word to PDF Converter</li>
+          <li>PDF Compressor</li>
+          <li>Image Format Converter</li>
+          <li>Video to GIF Creator</li>
+          <li>Word Counter</li>
+          <li>Text Cleaner & Formatter</li>
+        </ul>
+
+        <h2>Contact</h2>
+        <p>
+          Have feedback or feature requests? Reach out at{' '}
+          <a href="mailto:support@example.com">support@example.com</a>.
+        </p>
+      </div>
+    </>
+  );
+}