Apply and Save Imported Tasks

Once the imported data passes validation, replace the current task array contents and save the result.

If tasks is declared with const, update the existing array instead of assigning a new array:

tasks.splice(0, tasks.length, ...importedTasks);
saveTasks();
renderTasks();

Reset the file input afterward so the same file can be selected again if needed:

importInput.value = "";

Checkpoint

Export your tasks, change the list, and then import the exported file. The original task data and order should return.