Implement multi-domain SEO improvements:

- Add metadata to login and login-verify pages to prevent indexing.
- Update robots.txt to disallow additional sensitive paths.
- Enhance sitemap generation to filter by city and include accurate last modified dates.
- Refactor canonical URL generation to support multi-domain architecture, ensuring self-canonicalization for city domains.
- Remove deprecated CanonicalHandler component and streamline canonical URL handling.
- Introduce safe JSON-LD output to prevent XSS vulnerabilities.
- Add payment layout with appropriate metadata to prevent indexing.
- Conduct a comprehensive technical SEO audit and implement necessary fixes across the application.

components/CanonicalHandler.js

@@ -1,36 +0,0 @@
-'use client';
-
-import { useEffect } from 'react';
-import { getCanonicalUrlClient } from '@/lib/getCanonicalUrl';
-
-/**
- * Client-side canonical URL handler
- * Use this component in pages that need dynamic canonical URLs
- * that can't be determined at build time or in generateMetadata
- */
-export default function CanonicalHandler() {
-    useEffect(() => {
-        // Only run on client side
-        if (typeof window === 'undefined') return;
-
-        const canonicalUrl = getCanonicalUrlClient();
-
-        if (canonicalUrl) {
-            // Check if canonical link already exists
-            let canonicalLink = document.querySelector('link[rel="canonical"]');
-
-            if (canonicalLink) {
-                // Update existing canonical link
-                canonicalLink.href = canonicalUrl;
-            } else {
-                // Create new canonical link
-                canonicalLink = document.createElement('link');
-                canonicalLink.rel = 'canonical';
-                canonicalLink.href = canonicalUrl;
-                document.head.appendChild(canonicalLink);
-            }
-        }
-    }, []);
-
-    return null; // This component doesn't render anything
-}