feat: add weekly sales tab with WoW growth

services/dataProcessor.ts

@@ -509,6 +509,7 @@ export const mergeSalesAndAdsData = (salesData: SalesRecord[], adsData: AdsRecor
             marketplace: sale.customer,
             customer: sale.customer,
             month: sale.month,
+            week: sale.week || 0, // Preserve week info
             year: sale.year,
             asin: sale.asin,
             title: sale.title,
@@ -1252,4 +1253,58 @@ export const aggregateForComparisonTimeSeries = (data: SalesRecord[]): Compariso
             return Object.values(d).some(val => typeof val === 'number' && val > 0);
         })
         .sort((a, b) => a.week - b.week);
-};
+};
+export interface WeeklyPivotRow {
+    id: string;
+    sku: string;
+    title: string;
+    asin: string;
+    line: string;
+    customer: string;
+    unitsByWeek: { [weekKey: string]: number }; // Key: "YYYY-WW"
+}
+
+export const pivotWeeklySalesData = (data: CombinedKPIs[]): { 
+    rows: WeeklyPivotRow[], 
+    weeks: string[] 
+} => {
+    // 1. Identify all unique weeks and sort descending (YYYY-WW)
+    const weekKeys = new Set<string>();
+    data.forEach(d => {
+        if (d.week) {
+            const weekKey = `${d.year}-${String(d.week).padStart(2, '0')}`;
+            weekKeys.add(weekKey);
+        }
+    });
+    const sortedWeeks = Array.from(weekKeys).sort((a, b) => b.localeCompare(a));
+
+    const map = new Map<string, WeeklyPivotRow>();
+
+    data.forEach(record => {
+        const key = record.sku || record.asin || `${record.title}-${record.line}`;
+        if (!key) return;
+
+        if (!map.has(key)) {
+            map.set(key, {
+                id: key,
+                sku: record.sku || '',
+                title: record.title || '',
+                asin: record.asin || '',
+                line: record.line || '',
+                customer: record.customer || record.marketplace || '',
+                unitsByWeek: {}
+            });
+        }
+
+        const row = map.get(key)!;
+        if (record.week) {
+            const weekKey = `${record.year}-${String(record.week).padStart(2, '0')}`;
+            row.unitsByWeek[weekKey] = (row.unitsByWeek[weekKey] || 0) + record.unitsTotal;
+        }
+    });
+
+    return {
+        rows: Array.from(map.values()),
+        weeks: sortedWeeks
+    };
+};