feat: export PDF del piano settimanale

GET /me/meal-plans/export.pdf restituisce un PDF stampabile del piano
ACTIVE: 7 giorni × pasti con macros giornalieri + per-pasto + tempo
preparazione, gestione free-meal e giorni di digiuno completo, ultima
pagina con lista spesa aggregata per reparto.

- apps/api/.../plan/export.routes.ts: pdfkit, layout A4 con paginazione
  automatica e footer disclaimer su tutte le pagine
- apps/web/.../api/plan-export: proxy Next.js per same-origin + cookie
- apps/web/.../plan/page.tsx: aggiunto link "Esporta PDF ↗" accanto a
  "Lista della spesa" nell'header del piano

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

apps/web/src/app/[locale]/plan/page.tsx

@@ -90,12 +90,22 @@ function PlanPageContent({ plan }: { plan: Awaited<ReturnType<typeof fetchCurren
               </Button>
             </form>
             {plan ? (
-              <Link
-                href="/shopping"
-                className="text-ink-soft decoration-pomodoro hover:text-ink font-mono text-[11px] uppercase tracking-widest underline decoration-[1.5px] underline-offset-[5px] transition-colors"
-              >
-                Lista della spesa →
-              </Link>
+              <>
+                <Link
+                  href="/shopping"
+                  className="text-ink-soft decoration-pomodoro hover:text-ink font-mono text-[11px] uppercase tracking-widest underline decoration-[1.5px] underline-offset-[5px] transition-colors"
+                >
+                  {t('linkShopping')} →
+                </Link>
+                <a
+                  href="/api/plan-export"
+                  target="_blank"
+                  rel="noopener noreferrer"
+                  className="text-ink-soft decoration-pomodoro hover:text-ink font-mono text-[11px] uppercase tracking-widest underline decoration-[1.5px] underline-offset-[5px] transition-colors"
+                >
+                  {t('exportPdf')} ↗
+                </a>
+              </>
             ) : null}
           </div>
         </div>

apps/web/src/app/api/plan-export/route.ts

@@ -0,0 +1,32 @@
+// Proxy verso l'API: scarica il PDF del piano settimanale.
+
+import { headers } from 'next/headers';
+import { NextResponse } from 'next/server';
+
+export const dynamic = 'force-dynamic';
+
+const API_URL = process.env.API_URL ?? 'http://localhost:4000';
+
+export async function GET(): Promise<Response> {
+  const cookie = headers().get('cookie') ?? '';
+  const upstream = await fetch(`${API_URL}/me/meal-plans/export.pdf`, {
+    headers: { cookie },
+    cache: 'no-store',
+  });
+  if (!upstream.ok) {
+    return NextResponse.json(
+      { error: `api_error_${upstream.status}` },
+      { status: upstream.status },
+    );
+  }
+  const buffer = await upstream.arrayBuffer();
+  return new NextResponse(buffer, {
+    status: 200,
+    headers: {
+      'Content-Type': 'application/pdf',
+      'Content-Disposition':
+        upstream.headers.get('content-disposition') ?? 'attachment; filename="ketopath-piano.pdf"',
+      'Cache-Control': 'no-store',
+    },
+  });
+}