[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/assets/icons/icon.svg

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" width="512" height="512" viewBox="0 0 512 512" role="img" aria-label="NIS2 Agile">
+  <title>NIS2 Agile</title>
+  <!-- Italy-blue rounded tile -->
+  <rect x="40.96" y="40.96" width="430.08" height="430.08" rx="92.16" ry="92.16" fill="#0066CC"/>
+  <!-- White shield -->
+  <polygon points="114.7,99.3 397.3,99.3 395.9,202.2 386.0,263.7 360.6,325.1 315.4,386.6 256.0,428.0 196.6,386.6 151.4,325.1 126.0,263.7 116.1,202.2 114.7,99.3" fill="#FFFFFF"/>
+  <!-- Negative blue check -->
+  <polygon points="169.6,269.9 227.6,321.5 254.3,319.2 351.1,196.6 322.2,173.8 225.4,296.3 252.1,294.0 194.1,242.4" fill="#0066CC"/>
+</svg>