M8-T18: add source and multi-commodity meter UI

frontend/src/pages/EnergyPage.test.tsx

@@ -15,6 +15,7 @@
 
 import { describe, it, expect, vi, beforeEach } from 'vitest'
 import { screen, waitFor, fireEvent } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
 import { renderWithProviders } from '../test-utils'
 import { EnergyPage } from './EnergyPage'
 
@@ -135,6 +136,19 @@ describe('EnergyPage — device list', () => {
   })
 })
 
+describe('EnergyPage — M8 navigation labels', () => {
+  beforeEach(() => { vi.clearAllMocks(); setupDefaultMocks() })
+  it('has keyboard-operable Sources, Modbus Devices and Meters tabs, without a DSMR tab', async () => {
+    const user = userEvent.setup(); renderEnergy()
+    const sources = screen.getByRole('tab', { name: 'Sources' })
+    expect(screen.getByRole('tab', { name: 'Modbus Devices' })).toBeInTheDocument()
+    expect(screen.getByRole('tab', { name: 'Meters' })).toBeInTheDocument()
+    expect(screen.queryByRole('tab', { name: /^DSMR$/ })).not.toBeInTheDocument()
+    sources.focus(); await user.keyboard('{Enter}')
+    expect(await screen.findByTestId('panel-sources')).toBeInTheDocument()
+  })
+})
+
 describe('EnergyPage — create device', () => {
   beforeEach(() => {
     vi.clearAllMocks()