fix: add page navigation to Sidebar + wire in camel SVG logo

- Add Navigation section (Dashboard, Metrics, Agents) with useNavigate
- Route items now navigate to /routes/:id
- Active state highlights current page based on location.pathname
- Replace inline CamelIcon with actual camel-logo.svg asset

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/design-system/layout/Sidebar/Sidebar.module.css

@@ -17,6 +17,13 @@
   flex-shrink: 0;
 }
 
+.logoImg {
+  width: 28px;
+  height: 24px;
+  color: var(--amber-light);
+  filter: brightness(0) saturate(100%) invert(76%) sepia(30%) saturate(400%) hue-rotate(5deg) brightness(95%);
+}
+
 .brand {
   font-family: var(--font-mono);
   font-weight: 600;
@@ -132,6 +139,18 @@
   padding-left: 22px;
 }
 
+.navIcon {
+  font-size: 14px;
+  width: 18px;
+  text-align: center;
+  color: var(--sidebar-muted);
+  flex-shrink: 0;
+}
+
+.item.active .navIcon {
+  color: var(--amber-light);
+}
+
 .routeArrow {
   color: var(--sidebar-muted);
   font-size: 10px;