[FEAT] i18n IT/EN, Help Online contestuale, pagina Architettura

- i18n.js: sistema traduzioni IT/EN con ~150 chiavi, localStorage, data-i18n
- help.js: help contestuale per 10 pagine con riferimenti NIS2
- architecture.html: descrizione architettura sistema completa
- common.js: language toggle sidebar (IT/EN), link Architettura, icone
- Integrato i18n + help in tutte le 14 pagine app + 3 admin

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

public/admin/index.html

@@ -295,10 +295,12 @@
 
     <script src="/nis2/js/api.js"></script>
     <script src="/nis2/js/common.js"></script>
+    <script src="/nis2/js/i18n.js"></script>
     <script>
         // ── Auth check ───────────────────────────────────────────
         if (!checkAuth()) throw new Error('Not authenticated');
         loadSidebar();
+        I18n.init();
 
         // ── Admin check ──────────────────────────────────────────
         (async function checkAdmin() {

public/admin/organizations.html

@@ -130,10 +130,12 @@
 
     <script src="/nis2/js/api.js"></script>
     <script src="/nis2/js/common.js"></script>
+    <script src="/nis2/js/i18n.js"></script>
     <script>
         // ── Auth check ───────────────────────────────────────────
         if (!checkAuth()) throw new Error('Not authenticated');
         loadSidebar();
+        I18n.init();
 
         let currentPage = 1;
 

public/admin/users.html

@@ -150,10 +150,12 @@
 
     <script src="/nis2/js/api.js"></script>
     <script src="/nis2/js/common.js"></script>
+    <script src="/nis2/js/i18n.js"></script>
     <script>
         // ── Auth check ───────────────────────────────────────────
         if (!checkAuth()) throw new Error('Not authenticated');
         loadSidebar();
+        I18n.init();
 
         let currentPage = 1;