feat(task-management): enhance task list with drag-and-drop functionality and improved styling

- Integrated drag-and-drop capabilities using @dnd-kit for task reordering within the TaskListV2 component.
- Updated TaskGroupHeader to dynamically adjust colors based on group properties, improving visual clarity.
- Refactored TaskRow to support drag-and-drop interactions and optimized rendering of task details.
- Enhanced Redux state management for collapsed groups, transitioning from Set to array for better compatibility.
- Improved task display logic to handle optional fields and ensure consistent rendering across components.

worklenz-frontend/src/utils/colorUtils.ts

@@ -1,3 +1,20 @@
 export const tagBackground = (color: string): string => {
   return `${color}1A`; // 1A is 10% opacity in hex
 };
+
+export const getContrastColor = (hexcolor: string): string => {
+  // If a color is not a valid hex, default to a sensible contrast
+  if (!/^#([A-Fa-f0-9]{3}){1,2}$/.test(hexcolor)) {
+    return '#000000'; // Default to black for invalid colors
+  }
+
+  const r = parseInt(hexcolor.slice(1, 3), 16);
+  const g = parseInt(hexcolor.slice(3, 5), 16);
+  const b = parseInt(hexcolor.slice(5, 7), 16);
+
+  // Perceptual luminance calculation (from WCAG 2.0)
+  const luminance = (0.299 * r + 0.587 * g + 0.114 * b) / 255;
+
+  // Use a threshold to decide between black and white text
+  return luminance > 0.5 ? '#000000' : '#FFFFFF';
+};