feat: add TypeScript lessons and learning panel

- Introduced a new script to check TypeScript lesson files for errors.
- Created a main TypeScript file to render lessons and their details.
- Added lesson definitions with starter and answer codes.
- Implemented a user interface for navigating and running lessons.
- Styled the application with CSS for a better user experience.
- Updated README to reflect the new TypeScript section and usage instructions.

04-dom-events-async/04-click-counter/answer.js

@@ -0,0 +1,25 @@
+let count = 0;
+
+const value = document.getElementById("value");
+const decreaseButton = document.getElementById("decrease-btn");
+const increaseButton = document.getElementById("increase-btn");
+const resetButton = document.getElementById("reset-btn");
+
+function render() {
+  value.textContent = count;
+}
+
+decreaseButton.addEventListener("click", function () {
+  count -= 1;
+  render();
+});
+
+increaseButton.addEventListener("click", function () {
+  count += 1;
+  render();
+});
+
+resetButton.addEventListener("click", function () {
+  count = 0;
+  render();
+});