feat(03-02): extend dashboard with live ops sections

- Core counters: messages processed, sessions, queue depth, uptime, active requests, errors
- Model performance table: recent calls with latency, tokens/sec, provider, status
- Event stream: scrollable log with color-coded levels (error/warn/info)
- Active requests: in-flight request table with session, channel, duration
- Channels grid: existing channel status cards preserved
- Dual timer refresh: 3s for metrics/events/requests, 10s for health/channels
- Targeted DOM updates via getElementById for flicker-free fast updates

src/gateway/ui/style.css

@@ -1120,6 +1120,52 @@ tr:hover td {
   font-size: var(--font-size-base);
 }
 
+/* ── Event Stream ──────────────────────────────────────── */
+.event-stream {
+  max-height: 300px;
+  overflow-y: auto;
+  background-color: var(--bg-secondary);
+  border: 1px solid var(--border);
+  border-radius: var(--radius);
+  padding: 8px;
+  font-size: var(--font-size-sm);
+  font-family: var(--font-mono);
+}
+
+.event-row {
+  padding: 4px 8px;
+  border-bottom: 1px solid var(--border-light);
+  white-space: pre-wrap;
+  word-break: break-word;
+}
+
+.event-row:last-child {
+  border-bottom: none;
+}
+
+.event-level-error { color: var(--error); }
+.event-level-warn { color: var(--warning); }
+.event-level-info { color: var(--text-secondary); }
+
+/* ── Model Metrics Summary ─────────────────────────────── */
+.metrics-summary {
+  display: flex;
+  gap: 24px;
+  margin-bottom: 12px;
+  font-size: var(--font-size-sm);
+  color: var(--text-secondary);
+}
+
+.metrics-summary .metric {
+  display: flex;
+  gap: 6px;
+}
+
+.metrics-summary .metric-value {
+  font-weight: 600;
+  color: var(--text-primary);
+}
+
 /* ── Responsive: Mobile ─────────────────────────────────────── */
 
 @media (max-width: 768px) {