refactor: add dynamic input height, agent sorting, and last activity tracking

packages/app/src/utils/time.ts

@@ -0,0 +1,37 @@
+/**
+ * Format a date as a human-friendly relative time string
+ * Examples: "just now", "5m ago", "2h ago", "3d ago", "Jan 15"
+ */
+export function formatTimeAgo(date: Date): string {
+  const now = new Date();
+  const diffMs = now.getTime() - date.getTime();
+  const diffSec = Math.floor(diffMs / 1000);
+  const diffMin = Math.floor(diffSec / 60);
+  const diffHour = Math.floor(diffMin / 60);
+  const diffDay = Math.floor(diffHour / 24);
+
+  if (diffSec < 10) {
+    return "just now";
+  }
+
+  if (diffMin < 1) {
+    return `${diffSec}s ago`;
+  }
+
+  if (diffHour < 1) {
+    return `${diffMin}m ago`;
+  }
+
+  if (diffDay < 1) {
+    return `${diffHour}h ago`;
+  }
+
+  if (diffDay < 7) {
+    return `${diffDay}d ago`;
+  }
+
+  // For older dates, show abbreviated month and day
+  const month = date.toLocaleDateString("en-US", { month: "short" });
+  const day = date.getDate();
+  return `${month} ${day}`;
+}