// ================================================================
// That's it! All core concepts used:
// - Variables: let tasks, const taskListEl, etc.
// - Functions: renderTasks, addTask, deleteTask, toggleTaskDone,
// editTask, updateStats
// - Arrays: tasks[] storing objects { text, done }
// - Loops: for loop in renderTasks() and updateStats()
// - DOM: getElementById, createElement, appendChild,
// innerHTML, textContent, classList, addEventListener
// ================================================================