[Feat] Add Search and Filter Functionality for Tasks

**Is your feature request related to a problem? Please describe.**
Taskly currently lacks a robust search and filter feature, making it difficult for users to quickly locate specific tasks, especially as the number of tasks grows. Users may feel overwhelmed without a way to streamline their task view based on their preferences or priorities.

**Describe the solution you'd like**
Implement an advanced search and filter functionality that allows users to:
1. Search tasks by keywords in task titles or descriptions.
2. Filter tasks by:
- Due date (e.g., today, this week).
- Priority levels (e.g., high, medium, low).

Start by locating the task list and the task fields used for titles, descriptions, due dates, and priority. Define search and filter behavior for those fields, then verify that keyword searches and the requested due-date and priority filters narrow the visible task list as described.

Written by the indexing model from the issue text.