feat: add BreadcrumbProvider and e2e test suite

Add BreadcrumbProvider context so pages can override TopBar breadcrumbs
dynamically. Add Playwright e2e tests for dashboard, agents, routes,
exchanges, and admin pages.

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

e2e/agents.spec.ts

@@ -0,0 +1,80 @@
+import { test, expect } from '@playwright/test'
+
+test.describe('Agent Health (/agents)', () => {
+  test('renders stat cards and group cards', async ({ page }) => {
+    await page.goto('/agents')
+
+    // Stat strip
+    await expect(page.getByText('Total Agents')).toBeVisible()
+    await expect(page.getByText('Total TPS')).toBeVisible()
+
+    // Group cards for each application
+    await expect(page.getByText('order-service').first()).toBeVisible()
+    await expect(page.getByText('payment-svc').first()).toBeVisible()
+    await expect(page.getByText('notification-hub').first()).toBeVisible()
+
+    // Instance tables have data
+    const instanceRows = page.locator('table tbody tr')
+    expect(await instanceRows.count()).toBeGreaterThan(0)
+
+    // Instance table headers
+    await expect(page.getByRole('columnheader', { name: 'Instance' }).first()).toBeVisible()
+    await expect(page.getByRole('columnheader', { name: 'State' }).first()).toBeVisible()
+    await expect(page.getByRole('columnheader', { name: 'Uptime' }).first()).toBeVisible()
+    await expect(page.getByRole('columnheader', { name: 'TPS' }).first()).toBeVisible()
+
+    // Timeline section
+    await expect(page.getByText('Timeline').first()).toBeVisible()
+  })
+
+  test('clicking an instance row opens the detail panel', async ({ page }) => {
+    await page.goto('/agents')
+
+    // Click first instance row
+    const instanceRow = page.locator('table tbody tr').first()
+    await instanceRow.click()
+
+    // Detail panel opens — look for detail-specific labels
+    await expect(page.getByText('Version').first()).toBeVisible()
+    await expect(page.getByText('Throughput').first()).toBeVisible()
+  })
+
+  test('detail panel has Performance tab with charts', async ({ page }) => {
+    await page.goto('/agents')
+
+    // Click an instance to open detail panel
+    const instanceRow = page.locator('table tbody tr').first()
+    await instanceRow.click()
+
+    // Wait for panel to open
+    await expect(page.getByText('Version').first()).toBeVisible()
+
+    // DetailPanel tabs are plain buttons (not role="tab")
+    // Switch to Performance tab
+    const perfTab = page.getByRole('button', { name: 'Performance' })
+    await perfTab.click()
+
+    // Performance charts should render
+    await expect(page.getByText('Throughput (msg/s)').first()).toBeVisible()
+    await expect(page.getByText('Error Rate (err/h)').first()).toBeVisible()
+  })
+
+  test('app-scoped agents view', async ({ page }) => {
+    await page.goto('/agents/order-service')
+
+    // Breadcrumb/scope shows app
+    await expect(page.getByLabel('Breadcrumb').getByText('Agents')).toBeVisible()
+
+    // Only order-service agents should show
+    await expect(page.getByText('ord-1').first()).toBeVisible()
+    await expect(page.getByText('ord-2').first()).toBeVisible()
+    await expect(page.getByText('ord-3').first()).toBeVisible()
+  })
+
+  test('dead agent shows alert banner', async ({ page }) => {
+    await page.goto('/agents')
+
+    // notification-hub has a dead instance, should show alert
+    await expect(page.getByText('Single point of failure')).toBeVisible()
+  })
+})