Harden validation, improve runtime security and refactor core services

frontend/index.html

@@ -2,6 +2,7 @@
 <html lang="en">
 <head>
   <meta charset="UTF-8">
+  <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'wasm-unsafe-eval'; connect-src 'self'; style-src 'self' 'unsafe-inline'">
   <title>Anti-Scraper Demo</title>
 </head>
 <body>