Enhance security and localization features across the application

- Added rehype-sanitize plugin to the markdown configuration for improved security against XSS attacks.
- Updated environment variables in the codebase to include new configurations for SMTP and monitoring.
- Implemented secure headers in server and Nginx configurations to bolster security.
- Refactored email handling to prevent spoofing by ensuring safe sender addresses.
- Improved localization by updating language persistence and button components for better user experience.
- Enhanced the uptime API and contact form with better error handling and logging practices.
- Updated dependencies in package.json and package-lock.json for better performance and security.

nginx/nginx.conf

@@ -39,6 +39,15 @@ http {
         root /usr/share/nginx/html;
         index index.html index.htm;
 
+        # Security headers
+        add_header X-Content-Type-Options "nosniff" always;
+        add_header Referrer-Policy "strict-origin-when-cross-origin" always;
+        add_header Permissions-Policy "geolocation=(), camera=(), microphone=(), interest-cohort=()" always;
+        add_header Cross-Origin-Opener-Policy "same-origin" always;
+        add_header Cross-Origin-Embedder-Policy "require-corp" always;
+        add_header Strict-Transport-Security "max-age=31536000; includeSubDomains; preload" always;
+        add_header Content-Security-Policy "default-src 'self'; script-src 'self' 'wasm-unsafe-eval' 'nonce-astro'; style-src 'self' 'unsafe-inline'; img-src 'self' data: https://cdn.pixabay.com https://raw.githubusercontent.com; font-src 'self' data:; connect-src 'self'; frame-ancestors 'none'; base-uri 'self'; form-action 'self'" always;
+
         # Error pages
         error_page 404 /404.html;
         location = /404.html {