Reset tile scroll positions when switching incidents

Reset scrollTop on summary-content and factcheck-list containers
so scroll position from previous incident is not preserved.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/static/js/app.js

@@ -664,8 +664,10 @@ const App = {
 // Alte Inhalte sofort leeren um Flackern beim Wechsel zu vermeiden
         var el;
         el = document.getElementById("incident-title"); if (el) el.textContent = "";
+        el = document.getElementById("summary-content"); if (el) el.scrollTop = 0;
         el = document.getElementById("summary-text"); if (el) el.innerHTML = "";
         el = document.getElementById("factcheck-filters"); if (el) el.innerHTML = "";
+        el = document.querySelector(".factcheck-list"); if (el) el.scrollTop = 0;
         el = document.getElementById("factcheck-list"); if (el) el.innerHTML = "";
         el = document.getElementById("source-overview-content"); if (el) el.innerHTML = "";
         el = document.getElementById("timeline-entries"); if (el) el.innerHTML = "";