Add unread chat indicator

public/admin.css

@@ -95,6 +95,8 @@ label { display: grid; gap: 6px; color: var(--muted); font-size: 13px; }
 }
 .conversation-item.active { background: #eaf6f1; }
 .conversation-item.fresh { animation: pulse 1.2s ease-in-out 4; }
+.conversation-item.unread { background: #fffdf4; }
+.conversation-item.unread.active { background: #eaf6f1; }
 .conversation-open {
   min-width: 0;
   text-align: left;
@@ -108,6 +110,31 @@ label { display: grid; gap: 6px; color: var(--muted); font-size: 13px; }
 }
 .conversation-open:hover { filter: none; background: #f3f7f4; }
 .row { display: flex; justify-content: space-between; gap: 10px; align-items: center; }
+.visitor-row { min-width: 0; }
+.visitor-name-wrap {
+  min-width: 0;
+  display: inline-flex;
+  align-items: center;
+  gap: 7px;
+}
+.visitor-name-wrap strong {
+  min-width: 0;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+.unread-dot {
+  width: 9px;
+  height: 9px;
+  flex: 0 0 auto;
+  border-radius: 50%;
+  background: #c9d4ce;
+}
+.conversation-item.unread .unread-dot {
+  background: #ff3b30;
+  box-shadow: 0 0 0 0 rgb(255 59 48 / 55%);
+  animation: unreadPulse 1.25s ease-out infinite;
+}
 .status {
   font-size: 12px;
   color: white;
@@ -492,6 +519,12 @@ pre {
   50% { background: #dff7eb; }
 }
 
+@keyframes unreadPulse {
+  0% { box-shadow: 0 0 0 0 rgb(255 59 48 / 55%); }
+  70% { box-shadow: 0 0 0 8px rgb(255 59 48 / 0%); }
+  100% { box-shadow: 0 0 0 0 rgb(255 59 48 / 0%); }
+}
+
 @media (max-width: 820px) {
   body { overflow: auto; }
   .app { height: auto; min-height: 100vh; grid-template-columns: 1fr; overflow: visible; }