[DEPLOY] Migrazione a subdomain nis2.certisource.it

Rimozione prefisso /nis2/ da tutti i path frontend e router:
- index.php: basePath '' (da '/nis2')
- api.js: baseUrl '/api' (da '/nis2/api')
- Tutti i file HTML: path assoluti senza prefisso /nis2/

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

public/js/api.js

@@ -5,7 +5,7 @@
  */
 
 class NIS2API {
-    constructor(baseUrl = '/nis2/api') {
+    constructor(baseUrl = '/api') {
         this.baseUrl = baseUrl;
         this.token = localStorage.getItem('nis2_access_token');
         this.refreshToken = localStorage.getItem('nis2_refresh_token');
@@ -103,7 +103,7 @@ class NIS2API {
     logout() {
         this.post('/auth/logout', {}).catch(() => {});
         this.clearTokens();
-        window.location.href = '/nis2/login.html';
+        window.location.href = '/login.html';
     }
 
     getMe() { return this.get('/auth/me'); }