feat: add HTML lessons mode and side-by-side comparison UI

- Add HTML mode support with new validation types (element_exists,
  element_count, attribute_value, element_text, parent_child, sibling)
- Create 3 HTML lesson modules: Elements, Forms Basic, Forms Validation
- Implement side-by-side preview comparison (Your Output vs Expected)
- Add merge animation with "Perfect Match!" overlay on validation success
- Render expected output from solutionCode field in lesson JSON
- Update schema to support HTML mode and solutionCode
- Reorder modules: HTML first, then CSS, then Tailwind
- Update tests for new functionality

src/helpers/renderer.js

@@ -15,7 +15,7 @@ let feedbackTimeout = null;
  */
 export function renderModuleList(container, modules, onSelectModule, onSelectLesson) {
 	// Clear the container
-	container.innerHTML = "<h3>CSS Lessons</h3>";
+	container.innerHTML = "<h3>Lessons</h3>";
 
 	// Get user progress from localStorage
 	const progressData = localStorage.getItem("codeCrispies.progress");