fix(ui): показывать остановку потока live-трафика

tests/e2e/traffic-live.spec.ts

@@ -0,0 +1,34 @@
+import { test, expect } from '@playwright/test'
+
+for (const variant of ['closed', 'invalid', 'http-error'] as const) {
+  test(`Трафик: SSE ${variant} не выдаёт старое измерение за live`, async ({ page }) => {
+    const server = { id: '1', name: 'Тестовый сервер', site: 'TEST', country: 'RU', status: 'online', rxNow: 2, txNow: 3, rxPeak: 5, txPeak: 6, rxTotal: 100, txTotal: 200, sessions: 1, rxSeries: [1, 2], txSeries: [2, 3] }
+    await page.route('**/health', route => route.fulfill({ json: { ok: true } }))
+    await page.route('**/api/**', route => {
+      const path = new URL(route.request().url()).pathname
+      if (path.endsWith('/live')) {
+        if (variant === 'http-error') return route.fulfill({ status: 503, json: { error: 'Поток недоступен' } })
+        const sample = { rxMbps: 17, txMbps: 19, at: '2026-09-23T12:00:00Z' }
+        const body = 'event: sample\ndata: ' + JSON.stringify(sample) + '\n\n' + (variant === 'invalid' ? 'event: sample\ndata: {"rxMbps":null,"txMbps":-1}\n\n' : '')
+        return route.fulfill({ contentType: 'text/event-stream', body })
+      }
+      const json = path === '/api/auth/config' ? { required: false }
+        : path === '/api/traffic/servers' ? { servers: [server] }
+        : path === '/api/traffic/servers/1' ? { server }
+        : path.endsWith('/interfaces') || path === '/api/traffic/bound-interfaces' ? { interfaces: [] }
+        : path === '/api/traffic/users' ? { users: [] }
+        : path === '/api/servers' ? [] : {}
+      return route.fulfill({ json })
+    })
+    await page.goto('/traffic')
+    const summary = page.getByLabel('Скорость выбранного сервера')
+    await expect(summary).toBeVisible()
+    const hint = variant === 'http-error' ? 'История · live недоступен' : 'Последнее live-измерение · поток недоступен'
+    await expect(summary.getByText(hint, { exact: true }).filter({ visible: true })).toHaveCount(2)
+    await expect(summary.getByText('live', { exact: true })).toHaveCount(0)
+    if (variant !== 'http-error') {
+      await expect(summary).toContainText('17.0')
+      await expect(summary).toContainText('19.0')
+    }
+  })
+}