test(ci): add exporter heading levels and a11y typography smoke; update MAIN_PLAN

components/BuilderShell.test.tsx

@@ -0,0 +1,17 @@
+import { describe, it, expect } from 'vitest'
+import { render, screen } from '@testing-library/react'
+import React from 'react'
+import BuilderShell from '@/components/BuilderShell'
+
+describe('BuilderShell', () => {
+  it('좌/중/우 3패널과 접근성 라벨을 렌더링한다', () => {
+    render(
+      <BuilderShell left={<div>LEFT</div>} center={<div>CENTER</div>} right={<div>RIGHT</div>} />
+    )
+
+    expect(screen.getByTestId('builder-shell')).toBeInTheDocument()
+    expect(screen.getByLabelText('Components Panel')).toBeInTheDocument()
+    expect(screen.getByLabelText('Canvas')).toBeInTheDocument()
+    expect(screen.getByLabelText('Inspector')).toBeInTheDocument()
+  })
+})