Serverpuls: Zeitzone in Warnungen

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

tests/unit/serverpulsFormat.test.mjs

@@ -52,3 +52,10 @@ test('Zeitachse: deutsche Ausgabe in Europe/Berlin', () => {
   assert.equal(formatLegendTime(t), '30.09.2026, 11:20')
   assert.equal(formatLegendTime(null), '–')
 })
+
+test('formatSince: Europe/Berlin, unabhängig von der Prozess-Zeitzone', async () => {
+  const { formatSince } = await loadModule('src/lib/serverpulsFormat.js')
+  assert.equal(formatSince(Date.UTC(2026, 6, 1, 10, 0, 0)), '01.07.26, 12:00')
+  assert.equal(formatSince(Date.UTC(2026, 0, 1, 10, 0, 0)), '01.01.26, 11:00')
+  assert.equal(formatSince(0), '')
+})