Create an issue backlog page

[gabor-boros]

⚠️ Blocked on #322 and #303

Description

Develop the frontend page that displays the backlog of issues, providing users with an overview of all open and pending issues related to a project.

Currently, there is no dedicated backlog page to help users track and manage existing issues efficiently.

Tasks

• Implement the issue backlog page layout and UI.
• Integrate with the backend issue service to fetch and display issues.
• Support filtering, sorting, and backend pagination of issues.
• Add end-to-end tests to cover the page’s functionality.

Notes

• Follow existing UI design patterns and styles.
• Design will be provided upon assigning the task.