feat: Implement team member management endpoints and schemas

- Added endpoints for managing team members including:
  - Get team members
  - Add team member
  - Update member role
  - Remove team member
  - Transfer team ownership
- Enhanced existing team retrieval to include role information and member count.
- Introduced new schemas for team member management and responses.
- Updated TeamService with methods for member management, role updates, and ownership transfers.
- Added validation to ensure proper permissions and constraints on team operations.

Author: Lasim