feat(dashboard2): show last month's selling value alongside the delta

Selling card now reads "+12% vs previous · R 200,000" instead of just
"+12% vs previous". Optional previousValue prop on RepKpiCard; the other
3 cards don't pass it, so their format is unchanged.

src/app/(app)/dashboard2/page.tsx

@@ -185,6 +185,7 @@ export default function RepDashboardPage() {
           label="Selling this month"
           value={monthRevenue.sellingThisMonth}
           delta={deltaPct(monthRevenue.sellingThisMonth, monthRevenue.sellingLastMonth)}
+          previousValue={monthRevenue.sellingLastMonth}
           icon={DollarSign}
           accentColor={CHART.green}
           format="currency"
@@ -238,6 +239,7 @@ function RepKpiCard({
   icon: Icon,
   accentColor,
   format = "number",
+  previousValue,
 }: {
   label: string;
   value: number;
@@ -245,10 +247,20 @@ function RepKpiCard({
   icon: React.ComponentType<{ className?: string; style?: React.CSSProperties }>;
   accentColor: string;
   format?: "number" | "currency";
+  /** Optional previous-period value shown alongside the delta arrow
+   *  (e.g. "vs R 99,999 last month"). When omitted, the subline just
+   *  shows the percentage. */
+  previousValue?: number;
 }) {
   const positive = delta >= 0;
   const display =
     format === "currency" ? formatZar(value) : value.toLocaleString();
+  const previousDisplay =
+    previousValue !== undefined
+      ? format === "currency"
+        ? formatZar(previousValue)
+        : previousValue.toLocaleString()
+      : null;
   return (
     <DashboardCard accentColor={accentColor} padding="p-4">
       <div className="flex items-center justify-between gap-2 mb-2">
@@ -265,7 +277,7 @@ function RepKpiCard({
       </div>
       <div className="mt-0.5 text-[11px] font-semibold" style={{ color: positive ? CHART.green : CHART.red }}>
         {positive ? "+" : ""}
-        {delta}% vs previous
+        {delta}% vs previous{previousDisplay !== null ? ` · ${previousDisplay}` : ""}
       </div>
     </DashboardCard>
   );