fix(api): export PDF a 0 byte — bufferizza chunks pdfkit prima di send

Il pattern \`reply.send(doc)\` con uno stream pdfkit ha una race con fastify:
il body può chiudersi prima che pdfkit emetta tutti i chunks dopo \`doc.end()\`.

Ora colleziono i chunks in memoria, attendo \`doc.end()\` via Promise sull'evento
\`end\`, e mando il Buffer completo con \`Content-Length\` corretto. Applicato a
entrambi gli export (piano settimanale + tracking).

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

apps/api/src/modules/plan/export.routes.ts

@@ -52,9 +52,15 @@ export const planExportRoutes: FastifyPluginAsync = async (fastify) => {
       }
 
       const doc = new PDFDocument({ size: 'A4', margin: 50, bufferPages: true });
-      reply.header('Content-Type', 'application/pdf');
-      reply.header('Content-Disposition', 'attachment; filename="ketopath-piano.pdf"');
-      reply.send(doc);
+      // Bufferizziamo i chunks: fastify + pdfkit stream hanno una race se
+      // facciamo `reply.send(doc)` e poi `doc.end()`. Con il buffer chiudiamo
+      // il PDF prima di inviarlo e siamo sicuri che il body sia completo.
+      const chunks: Buffer[] = [];
+      doc.on('data', (c: Buffer) => chunks.push(c));
+      const done = new Promise<Buffer>((resolve, reject) => {
+        doc.on('end', () => resolve(Buffer.concat(chunks)));
+        doc.on('error', reject);
+      });
 
       // ── Header ───────────────────────────────────────────────────────────
       doc
@@ -225,6 +231,12 @@ export const planExportRoutes: FastifyPluginAsync = async (fastify) => {
       }
 
       doc.end();
+      const pdfBuffer = await done;
+      return reply
+        .header('Content-Type', 'application/pdf')
+        .header('Content-Disposition', 'attachment; filename="ketopath-piano.pdf"')
+        .header('Content-Length', String(pdfBuffer.length))
+        .send(pdfBuffer);
     },
   );
 };

apps/api/src/modules/tracking/export.routes.ts

@@ -39,10 +39,13 @@ export const trackingExportRoutes: FastifyPluginAsync = async (fastify) => {
     ]);
 
     const doc = new PDFDocument({ size: 'A4', margin: 50, bufferPages: true });
-
-    reply.header('Content-Type', 'application/pdf');
-    reply.header('Content-Disposition', 'attachment; filename="ketopath-export.pdf"');
-    reply.send(doc);
+    // Bufferizziamo i chunks per evitare race con fastify (vedi plan export).
+    const chunks: Buffer[] = [];
+    doc.on('data', (c: Buffer) => chunks.push(c));
+    const done = new Promise<Buffer>((resolve, reject) => {
+      doc.on('end', () => resolve(Buffer.concat(chunks)));
+      doc.on('error', reject);
+    });
 
     // ── Header ─────────────────────────────────────────────────────────
     doc
@@ -151,5 +154,11 @@ export const trackingExportRoutes: FastifyPluginAsync = async (fastify) => {
       );
 
     doc.end();
+    const pdfBuffer = await done;
+    return reply
+      .header('Content-Type', 'application/pdf')
+      .header('Content-Disposition', 'attachment; filename="ketopath-export.pdf"')
+      .header('Content-Length', String(pdfBuffer.length))
+      .send(pdfBuffer);
   });
 };