Fix bar chart hover on zero delivery days (#320)

Co-authored-by: Claude <noreply@anthropic.com>

apps/web/src/app/(dashboard)/dashboard/email-chart.tsx

@@ -139,7 +139,9 @@ export default function EmailChart({ days, domain }: EmailChartProps) {
               {/* <YAxis fontSize={12} className="font-mono" /> */}
               <Tooltip
                 content={({ payload }) => {
-                  const data = payload?.[0]?.payload as Record<
+                  if (!payload || payload.length === 0) return null;
+
+                  const data = payload[0]?.payload as Record<
                     | "sent"
                     | "delivered"
                     | "opened"
@@ -149,7 +151,16 @@ export default function EmailChart({ days, domain }: EmailChartProps) {
                     number
                   > & { date: string };
 
-                  if (!data || data.sent === 0) return null;
+                  if (!data) return null;
+
+                  const hasAnyData =
+                    (data.delivered || 0) > 0 ||
+                    (data.bounced || 0) > 0 ||
+                    (data.complained || 0) > 0 ||
+                    (data.opened || 0) > 0 ||
+                    (data.clicked || 0) > 0;
+
+                  if (!hasAnyData) return null;
 
                   return (
                     <div className=" bg-background border shadow-lg p-2 rounded-xl flex flex-col gap-2 px-4">