fix(ui): align Timeline panel header with Application Log

Both panels now use the same card wrapper (logStyles.logCard), header
container (logStyles.logHeader, 12px 16px padding), and DS SectionHeader
for the title. Previously Timeline rendered a custom 13px span while
Application Log used SectionHeader's uppercase style, so the two panels
side-by-side looked inconsistent.

Removes the now-orphaned .eventCard/.eventCardHeader/.sectionTitle and
.timelineCard/.timelineHeader CSS rules.

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

ui/src/pages/AgentHealth/AgentHealth.module.css

@@ -65,13 +65,6 @@
   align-self: flex-end;
 }
 
-/* Section header */
-.sectionTitle {
-  font-size: 13px;
-  font-weight: 600;
-  color: var(--text-primary);
-}
-
 .sectionMeta {
   font-size: 12px;
   color: var(--text-muted);
@@ -249,22 +242,6 @@
   margin-top: 20px;
 }
 
-/* Event card (timeline panel) — card styling via sectionStyles.section */
-.eventCard {
-  overflow: hidden;
-  display: flex;
-  flex-direction: column;
-  max-height: 420px;
-}
-
-.eventCardHeader {
-  display: flex;
-  align-items: center;
-  justify-content: space-between;
-  padding: 10px 16px;
-  border-bottom: 1px solid var(--border-subtle);
-}
-
 /* Compact app card */
 .compactCard {
   background: color-mix(in srgb, var(--card-accent) 8%, var(--bg-raised));