fix(web): ventas y compras envían la unidad de medida del artículo (UoMEntry)

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

apps/web/src/app/features/documents/document-model.ts

@@ -91,7 +91,11 @@ export function linesPayload(lines: readonly GridLine[], spec: LinesSpec = MARKE
     .filter((l) => !isBlankLine(l))
     .map((l) => {
       const out: DocRecord = {};
-      for (const f of spec.fields) if (!isEmpty(l[f])) out[f] = l[f];
+      for (const f of spec.fields) {
+        if (isEmpty(l[f])) continue;
+        if (f === 'UoMEntry' && !(Number(l[f]) > 0)) continue; // -1 = unidad manual: SAP no admite enviarla
+        out[f] = l[f];
+      }
       if (spec.base && hasBase(l)) for (const f of BASE_FIELDS) out[f] = l[f];
       return out;
     });