feat(web): PWA — manifest, icone, meta iOS

- src/app/manifest.ts (Next 14 file convention) → /manifest.webmanifest
- public/icons/icon.svg + icon-maskable.svg (vettoriali, palette editoriale)
- scripts/generate-icons.mjs (sharp): genera icon-192/512.png,
  apple-touch-icon-180.png, icon-maskable-512.png, badge-72.png
- layout.tsx: viewport con themeColor light/dark, manifest link,
  appleWebApp meta (capable + title), icons (svg + png + apple touch)
- .eslintrc: ignora scripts Node out-of-project; lint-staged: .mjs format-only

Display standalone, lang it, theme #221d18 (ink) / bg #f6f0df (carta).
Sblocca "Installa app" su Chrome/Edge/Android e "Aggiungi alla Home" su
iOS Safari — quest'ultimo è pre-requisito per ricevere le push su iOS.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

apps/web/public/icons/icon-maskable.svg

@@ -0,0 +1,8 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" role="img" aria-label="KetoPath">
+  <!-- Maskable: full-bleed background, contenuto entro safe area centrale (≈ 80%). -->
+  <rect width="512" height="512" fill="#f6f0df"/>
+  <!-- Wordmark centrato; nessun filetto perché può essere mascherato. -->
+  <text x="256" y="320" font-family="'Fraunces', 'Cormorant Garamond', 'Times New Roman', serif" font-size="240" font-weight="500" fill="#221d18" text-anchor="middle" letter-spacing="-10">
+    KP<tspan fill="#9a3f29">.</tspan>
+  </text>
+</svg>