feat(turnstile): integrate Cloudflare Turnstile for enhanced security in login and registration processes

types.d.ts

@@ -7,6 +7,14 @@ declare global {
     SITE_CONFIG: KVNamespace;
   }
 
+  interface Window {
+    turnstile?: {
+      render: (element: HTMLElement | string, options: Record<string, unknown>) => string
+      reset: (widgetId?: string) => void
+      remove: (widgetId: string) => void
+    }
+  }
+
   type Env = CloudflareEnv
 }
 
@@ -21,4 +29,4 @@ declare module "next-auth" {
   }
 }
 
-export type { Env }
+export type { Env }