feat: redesign Sidebar with hierarchical trees, starring, and collapsible sections

Replace flat app/route/agent lists with expandable tree navigation.
Apps contain their routes and agents hierarchically. Add localStorage-
backed starring with composite keys for uniqueness. Persist expand
state to sessionStorage across page navigations. Add collapsible
section headers, remove button on starred items, and parent app
context labels. Create stub pages for /apps/:id, /agents/:id,
/admin, /api-docs. Consolidate duplicated sidebar data into
shared mock. Widen sidebar from 220px to 260px.

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

src/pages/AgentHealth/AgentHealth.tsx

@@ -1,5 +1,4 @@
 import { useState } from 'react'
-import { useNavigate } from 'react-router-dom'
 import styles from './AgentHealth.module.css'
 
 // Layout
@@ -18,21 +17,7 @@ import { Card } from '../../design-system/primitives/Card/Card'
 
 // Mock data
 import { agents } from '../../mocks/agents'
-import { routes } from '../../mocks/routes'
-
-// ─── Sidebar data (shared) ────────────────────────────────────────────────────
-const APPS = [
-  { id: 'order-service', name: 'order-service', agentCount: 2, health: 'live' as const, exchangeCount: 1433 },
-  { id: 'payment-svc', name: 'payment-svc', agentCount: 1, health: 'live' as const, exchangeCount: 912 },
-  { id: 'shipment-tracker', name: 'shipment-tracker', agentCount: 2, health: 'live' as const, exchangeCount: 471 },
-  { id: 'notification-hub', name: 'notification-hub', agentCount: 1, health: 'stale' as const, exchangeCount: 128 },
-]
-
-const SIDEBAR_ROUTES = routes.slice(0, 3).map((r) => ({
-  id: r.id,
-  name: r.name,
-  exchangeCount: r.exchangeCount,
-}))
+import { SIDEBAR_APPS } from '../../mocks/sidebar'
 
 // ─── Build trend data for each agent ─────────────────────────────────────────
 function buildAgentTrendSeries(agentId: string) {
@@ -68,16 +53,8 @@ const totalActiveRoutes = agents.reduce((sum, a) => sum + a.activeRoutes, 0)
 
 // ─── AgentHealth page ─────────────────────────────────────────────────────────
 export function AgentHealth() {
-  const navigate = useNavigate()
-  const [activeItem, setActiveItem] = useState('agents')
   const [expandedAgent, setExpandedAgent] = useState<string | null>(null)
 
-  function handleItemClick(id: string) {
-    setActiveItem(id)
-    const route = routes.find((r) => r.id === id)
-    if (route) navigate(`/routes/${id}`)
-  }
-
   function toggleAgent(id: string) {
     setExpandedAgent((prev) => (prev === id ? null : id))
   }
@@ -85,13 +62,7 @@ export function AgentHealth() {
   return (
     <AppShell
       sidebar={
-        <Sidebar
-          apps={APPS}
-          routes={SIDEBAR_ROUTES}
-          agents={agents}
-          activeItem={activeItem}
-          onItemClick={handleItemClick}
-        />
+        <Sidebar apps={SIDEBAR_APPS} />
       }
     >
       {/* Top bar */}