fix(#112): add missing Routes section, fix admin double padding

Review feedback: buildRouteTreeNodes was defined but never rendered.
Added Routes section between Agents and Admin. Removed duplicate
padding on admin pages (AdminLayout handles its own padding).

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

ui/src/components/LayoutShell.tsx

@@ -26,6 +26,7 @@ import { useScope } from '../hooks/useScope';
 import {
   buildAppTreeNodes,
   buildAgentTreeNodes,
+  buildRouteTreeNodes,
   buildAdminTreeNodes,
   readCollapsed,
   writeCollapsed,
@@ -145,6 +146,7 @@ function makeChevron() {
 
 const SK_APPS = 'sidebar:section:apps';
 const SK_AGENTS = 'sidebar:section:agents';
+const SK_ROUTES = 'sidebar:section:routes';
 const SK_ADMIN = 'sidebar:section:admin';
 const SK_COLLAPSED = 'sidebar:collapsed';
 
@@ -181,10 +183,11 @@ function LayoutContent() {
   // --- Section open states ------------------------------------------
   const [appsOpen, setAppsOpen] = useState(() => readCollapsed(SK_APPS, true));
   const [agentsOpen, setAgentsOpen] = useState(() => readCollapsed(SK_AGENTS, false));
+  const [routesOpen, setRoutesOpen] = useState(() => readCollapsed(SK_ROUTES, false));
   const [adminOpen, setAdminOpen] = useState(() => readCollapsed(SK_ADMIN, false));
 
   // Ref to remember operational section states when switching to admin
-  const opsStateRef = useRef({ apps: appsOpen, agents: agentsOpen });
+  const opsStateRef = useRef({ apps: appsOpen, agents: agentsOpen, routes: routesOpen });
 
   const isAdminPage = location.pathname.startsWith('/admin');
 
@@ -193,9 +196,10 @@ function LayoutContent() {
   useEffect(() => {
     if (isAdminPage && !prevAdminRef.current) {
       // Entering admin — save operational states and collapse them
-      opsStateRef.current = { apps: appsOpen, agents: agentsOpen };
+      opsStateRef.current = { apps: appsOpen, agents: agentsOpen, routes: routesOpen };
       setAppsOpen(false);
       setAgentsOpen(false);
+      setRoutesOpen(false);
       setAdminOpen(true);
       writeCollapsed(SK_APPS, false);
       writeCollapsed(SK_AGENTS, false);
@@ -204,9 +208,11 @@ function LayoutContent() {
       // Leaving admin — restore operational states
       setAppsOpen(opsStateRef.current.apps);
       setAgentsOpen(opsStateRef.current.agents);
+      setRoutesOpen(opsStateRef.current.routes);
       setAdminOpen(false);
       writeCollapsed(SK_APPS, opsStateRef.current.apps);
       writeCollapsed(SK_AGENTS, opsStateRef.current.agents);
+      writeCollapsed(SK_ROUTES, opsStateRef.current.routes);
       writeCollapsed(SK_ADMIN, false);
     }
     prevAdminRef.current = isAdminPage;
@@ -235,6 +241,17 @@ function LayoutContent() {
     });
   }, [isAdminPage, navigate]);
 
+  const toggleRoutes = useCallback(() => {
+    if (isAdminPage) {
+      navigate('/exchanges');
+      return;
+    }
+    setRoutesOpen((prev) => {
+      writeCollapsed(SK_ROUTES, !prev);
+      return !prev;
+    });
+  }, [isAdminPage, navigate]);
+
   const toggleAdmin = useCallback(() => {
     setAdminOpen((prev) => {
       writeCollapsed(SK_ADMIN, !prev);
@@ -282,6 +299,11 @@ function LayoutContent() {
     [sidebarApps],
   );
 
+  const routeTreeNodes: SidebarTreeNode[] = useMemo(
+    () => buildRouteTreeNodes(sidebarApps, makeStatusDot, makeChevron),
+    [sidebarApps],
+  );
+
   const adminTreeNodes: SidebarTreeNode[] = useMemo(
     () => buildAdminTreeNodes(),
     [],
@@ -511,6 +533,24 @@ function LayoutContent() {
         />
       </Sidebar.Section>
 
+      <Sidebar.Section
+        icon={createElement(GitBranch, { size: 16 })}
+        label="Routes"
+        open={routesOpen}
+        onToggle={toggleRoutes}
+      >
+        <SidebarTree
+          nodes={routeTreeNodes}
+          selectedPath={sidebarRevealPath ?? location.pathname}
+          isStarred={isStarred}
+          onToggleStar={toggleStar}
+          filterQuery={filterQuery}
+          persistKey="routes"
+          autoRevealPath={sidebarRevealPath}
+          onNavigate={handleSidebarNavigate}
+        />
+      </Sidebar.Section>
+
       {/* When NOT on admin pages, show Admin section at bottom */}
       {!isAdminPage && (
         <Sidebar.Section
@@ -564,7 +604,7 @@ function LayoutContent() {
         <ContentTabs active={scope.tab} onChange={setTab} scope={scope} />
       )}
 
-      <main style={{ flex: 1, display: 'flex', flexDirection: 'column', overflow: 'hidden', minHeight: 0, padding: isAdminPage ? '1.5rem' : 0 }}>
+      <main style={{ flex: 1, display: 'flex', flexDirection: 'column', overflow: 'hidden', minHeight: 0 }}>
         <Outlet />
       </main>
     </AppShell>