[FEAT] Dashboard: card Documenti istituzionali funzionante + UI (ticket #499)

- loadDocs: 5 voci standard sempre presenti + voci custom + 'Aggiungi voce'
- modale add/edit con descrizione OBBLIGATORIA (richiesta punto 1), link doc opzionale
- delete voci custom; controlli visibili a org_admin/compliance_manager/super_admin
- CSS .doc-* in v3.css; cache-buster dashboard.js/v3.css su dashboard.html; version 1.25.1

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

public/dashboard.html

@@ -6,7 +6,7 @@
     <title>Dashboard · NIS2 Agile</title>
     <!-- UI V3: Inter self-host + design system v3.css (NO Google Fonts / NO unpkg CDN). -->
     <link rel="stylesheet" href="/vendor/inter/inter.css?v=20260627">
-    <link rel="stylesheet" href="/css/v3.css?v=20260627">
+    <link rel="stylesheet" href="/css/v3.css?v=20260724a">
   <!-- PWA:start -->
   <link rel="manifest" href="/manifest.webmanifest">
   <meta name="theme-color" content="#0066CC">
@@ -118,7 +118,7 @@
     <script src="/js/topnav-v3.js?v=20260627t"></script>
     <script src="/js/i18n.js?v=20260627p"></script>
     <script src="/js/help.js?v=20260627n"></script>
-    <script src="/js/dashboard.js?v=20260627"></script>
+    <script src="/js/dashboard.js?v=20260724a"></script>
     <script>
         // ── Auth check ───────────────────────────────────────────
         if (!checkAuth()) throw new Error('Not authenticated');