feat(custom-columns): enhance task management with custom column support

- Added custom column values to task responses in the API for better task management flexibility.
- Implemented custom column components in the frontend, including dropdowns and date pickers, to improve user interaction.
- Updated TaskListV2 and TaskRow components to handle custom columns, ensuring proper rendering and functionality.
- Introduced a new PeopleDropdown component for selecting team members in custom columns, enhancing usability.
- Enhanced styling for custom column components to support both light and dark modes, improving visual consistency.

worklenz-frontend/src/api/tasks/tasks.api.service.ts

@@ -29,6 +29,7 @@ export interface ITaskListConfigV2 {
   group?: string;
   isSubtasksInclude: boolean;
   include_empty?: string; // Include empty groups in response
+  customColumns?: boolean; // Include custom column values in response
 }
 
 export interface ITaskListV3Response {