[Feat] Implement pull-to-refresh for the task list.

[pranavkonidena]

Is your feature request related to a problem? Please describe.
Currently, there is no quick way for users to refresh the task list to check for updates or sync changes. A pull-to-refresh gesture would make this process more intuitive and user-friendly.

Describe the solution you'd like
Enable a pull-to-refresh gesture for the task list.
When the user pulls down on the list, a refresh indicator (like a spinning loader) should appear.
Once the refresh is complete, the updated task list should be displayed.
Design specifications:
Use Flutter’s RefreshIndicator widget to implement this functionality.
The refresh gesture should provide visual feedback, such as a progress indicator.
If no changes are detected, notify the user with a subtle message like:
"You're all caught up!"

Additional context
Ensure the refresh behavior does not interfere with the current scroll functionality.