Serverpuls: Zeitzone in Warnungen

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

src/lib/serverpulsFormat.js

@@ -89,3 +89,9 @@ export function formatLegendTime(sec) {
   if (sec === null || sec === undefined) return '–'
   return F.legend.format(new Date(sec * 1000))
 }
+
+// "seit"-Zeitpunkt in Warnungen, immer Berliner Zeit.
+export function formatSince(ts) {
+  if (!ts) return ''
+  return new Date(ts).toLocaleString('de-DE', { dateStyle: 'short', timeStyle: 'short', timeZone: 'Europe/Berlin' })
+}