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/scripts/generate-icons.mjs

@@ -0,0 +1,28 @@
+// Genera i PNG dell'icona PWA a partire dalle SVG sorgente.
+// Eseguilo dopo aver modificato icon.svg / icon-maskable.svg.
+//
+//   pnpm --filter @ketopath/web exec node scripts/generate-icons.mjs
+
+import { readFile, writeFile } from 'node:fs/promises';
+import { fileURLToPath } from 'node:url';
+import path from 'node:path';
+import sharp from 'sharp';
+
+const here = path.dirname(fileURLToPath(import.meta.url));
+const PUBLIC_ICONS = path.join(here, '..', 'public', 'icons');
+
+const targets = [
+  { src: 'icon.svg', out: 'icon-192.png', size: 192 },
+  { src: 'icon.svg', out: 'icon-512.png', size: 512 },
+  { src: 'icon.svg', out: 'apple-touch-icon.png', size: 180 },
+  { src: 'icon-maskable.svg', out: 'icon-maskable-512.png', size: 512 },
+  { src: 'icon-maskable.svg', out: 'badge-72.png', size: 72 },
+];
+
+for (const t of targets) {
+  const svg = await readFile(path.join(PUBLIC_ICONS, t.src));
+  const png = await sharp(svg, { density: 384 }).resize(t.size, t.size).png().toBuffer();
+  await writeFile(path.join(PUBLIC_ICONS, t.out), png);
+  // eslint-disable-next-line no-console
+  console.info(`✓ ${t.out} (${t.size}×${t.size})`);
+}