feat: add Vitest configuration and tests for lesson modules and rendering

vitest.config.js

@@ -0,0 +1,20 @@
+// vitest.config.js
+import { defineConfig } from 'vitest/config';
+
+export default defineConfig({
+    test: {
+        globals: true,
+        environment: 'jsdom',
+        setupFiles: ['./tests/setup.js'],
+        include: ['tests/**/*.{test,spec}.js'],
+        coverage: {
+            reporter: ['text', 'json', 'html'],
+            exclude: ['node_modules/', 'tests/setup.js']
+        },
+        server: {
+            deps: {
+                inline: true
+            }
+        }
+    }
+});