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

vitest.config.ts

@@ -0,0 +1,16 @@
+import { defineConfig } from 'vitest/config'
+import tsconfigPaths from 'vite-tsconfig-paths'
+
+export default defineConfig({
+  plugins: [tsconfigPaths()],
+  test: {
+    environment: 'jsdom',
+    setupFiles: ['./setupTests.ts'],
+    globals: true,
+    css: false,
+    coverage: {
+      provider: 'v8',
+      reportsDirectory: './coverage',
+    },
+  },
+})