[FEAT] PWA installabile Android/iOS conforme AGID (v1.15.0)

- manifest.webmanifest + service worker (offline shell, /api network-only, asset stale-while-revalidate)
- set icone (192/512 + maskable + apple-touch + favicon), generate zero-deps (pure Node+zlib)
- tag PWA + viewport viewport-fit=cover (zoom mantenuto, WCAG 1.4.4) in 77 pagine HTML
- AGID/WCAG 2.1 AA: touch target >=44px, orientamento/zoom liberi, safe-area standalone
- generatori riproducibili: scripts/gen-pwa-icons.mjs + scripts/inject-pwa-head.mjs
- bump version 1.14.1 -> 1.15.0

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

public/index.html

@@ -2,7 +2,7 @@
 <html lang="it">
 <head>
     <meta charset="UTF-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta name="viewport" content="width=device-width, initial-scale=1, viewport-fit=cover">
     <title>NIS2 Agile — Compliance NIS2 semplificata per aziende e consulenti</title>
     <meta name="description" content="Piattaforma SaaS multi-tenant per la compliance NIS2 (EU 2022/2555 e D.Lgs. 138/2024). Doppia gap analysis Art.21 e misure di base ACN (Det. 164179/2025), risk management, incident response Art.23, portale fornitori e AI consulente ancorata alle fonti normative certe.">
     <link rel="canonical" href="https://nis2.agile.software/">
@@ -693,6 +693,19 @@
     <link rel="stylesheet" href="mobile-conversion.css?v=20260519a">
 <!-- Plausible Analytics -->
 <script defer data-domain="nis2.agile.software" src="https://analytics.agile.software/js/script.js"></script>
+  <!-- PWA:start -->
+  <link rel="manifest" href="/manifest.webmanifest">
+  <meta name="theme-color" content="#0066CC">
+  <link rel="icon" type="image/png" sizes="32x32" href="/assets/icons/favicon-32.png">
+  <link rel="icon" type="image/png" sizes="16x16" href="/assets/icons/favicon-16.png">
+  <link rel="apple-touch-icon" sizes="180x180" href="/assets/icons/apple-touch-icon.png">
+  <meta name="apple-mobile-web-app-capable" content="yes">
+  <meta name="mobile-web-app-capable" content="yes">
+  <meta name="apple-mobile-web-app-status-bar-style" content="default">
+  <meta name="apple-mobile-web-app-title" content="NIS2 Agile">
+  <meta name="application-name" content="NIS2 Agile">
+  <script src="/js/pwa.js?v=20260614" defer></script>
+  <!-- PWA:end -->
 </head>
 <body>