No confirmation or visual feedback after adding a task — multiple duplicate tasks created

When I click on the “Add Task” button in the to-do list form, the button hovers (indicating it’s clickable), but there is no clear confirmation that the task has been added successfully.
Because of this, I ended up clicking the button multiple times, thinking it wasn’t working — and later found the same task added 10 times.

♦️Steps to Reproduce:
1. Open the “Add Task” form.
2. Fill in the task details (e.g., title, dates, etc.).
3. Click on the “Add Task” button.
Notice that:
The button briefly hovers, but no message or visible feedback appears.
After closing the form, you see the same task added multiple times.

♦️ Expected Behavior:
After clicking “Add Task”, the app should:
1. Show a success message or toast notification like “Task added successfully ✅”.
2. Disable the button temporarily or close the modal.
3. Optionally refresh or highlight the newly added task.

♦️ Actual Behavior:
1. The button remains hover-highlighted.
2. No success feedback.
3. Allows multiple clicks, causing multiple duplicate tasks.

♦️ Possible Solutions:
1. Add a loading or disabled state to the “Add Task” button while processing.
2. Show a toast or modal message confirming successful task creation.
3. Automatically close the task creation form once the task is added.

Start by reproducing the duplicate-task behavior from the Add Task form and trace the JavaScript handler for the button. Confirm the task is created only once and that the form provides visible success feedback or prevents repeated submission.

Written by the indexing model from the issue text.