Site Health: Add common cache headers for improved caching diagnostics

Author: AKSHAT2802

src/wp-admin/includes/class-wp-site-health.php

@@ -3412,6 +3412,16 @@ public function get_page_cache_headers() {
 			},
 			'x-srcache-store-status' => $cache_hit_callback,
 			'x-srcache-fetch-status' => $cache_hit_callback,
+
+			// Generic caching proxies (Nginx, Varnish, etc.)
+			'x-cache' => $cache_hit_callback,
+			'x-cache-status' => $cache_hit_callback,
+			
+			// Cloudflare
+			'cf-cache-status' => $cache_hit_callback,
+			
+			// Apache mod_cache
+			'x-cache-detail' => $cache_hit_callback,			
 		);
 
 		/**