fix(ui): различать нулевые и неизвестные счётчики WireGuard

tests/e2e/wireguard-tables.spec.ts

@@ -45,3 +45,23 @@ test("WireGuard: пустые интерфейсы и пиры", async ({ page }
   await page.getByRole("tab", { name: /Пиры/ }).click()
   await expect(page.getByText("Нет пиров", { exact: true })).toBeVisible()
 })
+
+for (const view of ["details", "peers"] as const) test("WireGuard traffic: observed zero differs from missing/" + view, async ({ page }) => {
+  await setup(page)
+  const interfaces = fixture.interfaces.map((row, i) => ({ ...row, peers: row.peers.map(peer => {
+    const { transferRx, transferTx, ...config } = peer
+    return i === 0 ? { ...config, transferRx: 0, transferTx: 0 } : i === 1 ? config : { ...config, transferRx, transferTx }
+  }) }))
+  await page.route("**/api/wireguard", route => route.fulfill({ json: wgListResponseSchema.parse({ interfaces }) }))
+  await page.reload()
+  const rows = page.locator("tr[data-row-id]")
+  if (view === "peers") await page.getByRole("tab", { name: /Пиры/ }).click()
+  for (const [index, value] of [[0, "0 Б"], [1, "—"], [2, "3 Б"]] as const) {
+    const row = rows.nth(index)
+    if (view === "details") await row.click()
+    const target = view === "details" ? row.locator("xpath=following-sibling::tr[1]") : row
+    await expect(target.getByLabel("RX", { exact: true })).toHaveText(value)
+    await expect(target.getByLabel("TX", { exact: true })).toHaveText(value)
+    if (view === "details") await row.click()
+  }
+})