fix(ui): Timeline uses EventFeed's internal scroll + load-older button

EventFeed has its own search + filter toolbar inside the component.
Wrapping it in InfiniteScrollArea made the toolbar scroll out of
sight. Drop InfiniteScrollArea for the Timeline, give EventFeed a
bounded-height flex container (it scrolls its own .list internally),
and add an explicit 'Load older events' button for cursor
pagination. Polling always on for events (low volume).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

ui/src/styles/log-panel.module.css

@@ -129,3 +129,36 @@
   align-items: center;
   gap: 6px;
 }
+
+/* Timeline: EventFeed owns its own scroll (so its internal search/filter
+   toolbar stays pinned). Give it a bounded height and let its .list scroll.
+   Pagination via the explicit "Load older" button below, not scroll. */
+.eventFeedContainer {
+  display: flex;
+  flex-direction: column;
+  max-height: 360px;
+  min-height: 0;
+  overflow: hidden;
+}
+
+.loadOlderBtn {
+  padding: 8px 12px;
+  border: none;
+  border-top: 1px solid var(--border-subtle);
+  background: var(--bg-surface);
+  color: var(--text-muted);
+  font-size: 12px;
+  cursor: pointer;
+  text-align: center;
+  font-family: var(--font-body);
+}
+
+.loadOlderBtn:hover:not(:disabled) {
+  color: var(--text-primary);
+  background: var(--bg-hover);
+}
+
+.loadOlderBtn:disabled {
+  opacity: 0.5;
+  cursor: not-allowed;
+}