feat: vernostne zlavy - pri neparnom pocte je prvy produkt cez cely riadok

Parny pocet: vsetky produkty po 2 v riadku. Neparny: prvy produkt sam cez
celu sirku (vacsi vizual), ostatne po 2. Export obrazkov kariet pouziva
rovnaku sirku karty ako nahlad.

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

src/lib/productCard.ts

@@ -372,23 +372,46 @@ export function renderProductCard(p: CardProduct, ctx: CardContext): string {
     </table>`;
 }
 
-// Mriežka kariet (1 alebo 2 na riadok) s rovnakou výškou kariet v riadku
-export function renderProductGrid(products: CardProduct[], ctx: CardContext): string {
-  const cols = ctx.cardWidth > 300 ? 1 : 2;
-  const rows: CardProduct[][] = [];
-  for (let i = 0; i < products.length; i += cols) rows.push(products.slice(i, i + cols));
-  return rows
+// Kontext konkrétnej karty: vo vernostných zľavách pri nepárnom počte je prvý produkt cez celý riadok
+export function cardContextFor(m: NewsletterModule, index: number, mode: RenderMode): CardContext {
+  const base = cardContextForModule(m, mode);
+  const count = (m.data.products || []).length;
+  if (base.variant === 'loyalty' && count % 2 === 1 && index === 0) return { ...base, cardWidth: 600 };
+  return base;
+}
+
+// Riadky mriežky (indexy produktov): 1 na riadok, alebo po 2;
+// vernostné zľavy s nepárnym počtom: prvý produkt sám cez celý riadok, ostatné po 2
+function gridRows(m: NewsletterModule, count: number, oneColumn: boolean): number[][] {
+  const idx = Array.from({ length: count }, (_, i) => i);
+  if (oneColumn) return idx.map((i) => [i]);
+  const rows: number[][] = [];
+  let start = 0;
+  if (m.type === 'loyalty_club' && count % 2 === 1) {
+    rows.push([0]);
+    start = 1;
+  }
+  for (let i = start; i < count; i += 2) rows.push(idx.slice(i, i + 2));
+  return rows;
+}
+
+// Mriežka kariet s rovnakou výškou kariet v riadku
+export function renderProductGrid(m: NewsletterModule, mode: RenderMode): string {
+  const products: CardProduct[] = m.data.products || [];
+  const oneColumn = cardContextForModule(m, mode).cardWidth > 300;
+  return gridRows(m, products.length, oneColumn)
     .map((row, rIdx) => {
       const spacer = rIdx > 0 ? '<tr><td height="12" style="font-size: 12px; line-height: 12px;">&nbsp;</td></tr>' : '';
       const cells = row
         .map(
-          (p, idx) => `
-                <td width="${cols === 1 ? 100 : 50}%" valign="top" height="1" style="${cols === 1 ? '' : idx === 0 ? 'padding-right: 6px;' : 'padding-left: 6px;'} height: 100%;">
-                    ${renderProductCard(p, ctx)}
+          (i, idx) => `
+                <td width="${row.length === 1 ? 100 : 50}%" valign="top" height="1" style="${row.length === 1 ? '' : idx === 0 ? 'padding-right: 6px;' : 'padding-left: 6px;'} height: 100%;">
+                    ${renderProductCard(products[i], cardContextFor(m, i, mode))}
                 </td>`
         )
         .join('');
-      const filler = cols === 2 && row.length === 1 ? '<td width="50%" style="padding-left: 6px;"></td>' : '';
+      // posledný riadok s 1 produktom v 2-stĺpcovej mriežke (bežné sekcie) – produkt ostane v ľavej polovici
+      const filler = !oneColumn && row.length === 1 && cardContextFor(m, row[0], mode).cardWidth <= 300 ? '<td width="50%" style="padding-left: 6px;"></td>' : '';
       return `${spacer}
         <tr>
             <td>