fix: apply parseUTC to dashboard, unify date helpers in date-utils.ts

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Co-authored-by: christianlouis <361235+christianlouis@users.noreply.github.com>

frontend/src/lib/date-utils.ts

@@ -14,3 +14,40 @@
 export function parseUTC(iso: string): Date {
   return new Date(/Z|[+-]\d{2}:?\d{2}$/.test(iso) ? iso : iso + 'Z');
 }
+
+/**
+ * Format an ISO-8601 UTC timestamp as a human-readable relative time string
+ * (e.g. "3m ago", "2h ago", "1d ago").  Returns "Never" for falsy input.
+ */
+export function formatRelative(iso?: string | null): string {
+  if (!iso) return 'Never';
+  const diff = Date.now() - parseUTC(iso).getTime();
+  const minutes = Math.floor(diff / 60000);
+  if (minutes < 1) return 'Just now';
+  if (minutes < 60) return `${minutes}m ago`;
+  const hours = Math.floor(minutes / 60);
+  if (hours < 24) return `${hours}h ago`;
+  return `${Math.floor(hours / 24)}d ago`;
+}
+
+/**
+ * Format an ISO-8601 UTC timestamp as a locale-aware short date + medium time
+ * string, e.g. "28.03.26, 22:19:44".
+ */
+export function formatDate(iso: string): string {
+  return parseUTC(iso).toLocaleString(undefined, {
+    dateStyle: 'short',
+    timeStyle: 'medium',
+  });
+}
+
+/**
+ * Format a duration in seconds as a human-readable string,
+ * e.g. "3.1s" or "2m 5s".  Returns "—" for null/undefined input.
+ */
+export function formatDuration(seconds?: number | null): string {
+  if (seconds == null) return '—';
+  if (seconds < 60) return `${seconds.toFixed(1)}s`;
+  const totalSecs = Math.floor(seconds);
+  return `${Math.floor(totalSecs / 60)}m ${totalSecs % 60}s`;
+}