Enhance: Graph Controller UI with teal theme and fix child item priority default

Graph Controller Enhancements:
- Transform dropdown with premium teal/cyan gradient theme throughout
- Add gradient top accent bar and enhanced header with icon
- Increase dropdown height from 320px to 600px (eliminate scrolling)
- Reduce action button sizes (p-2.5 → p-1.5, icons h-4 → h-3)
- Premium gradient backgrounds for edit (teal) and delete (red) buttons
- Enhanced hover animations with rotate, scale, and glow effects
- Consistent styling for disabled system graph buttons with proper accessibility
- Active graph cards with teal gradient borders and pulse indicators
- Enhanced folder headers with dynamic gradient icons and states
- Premium badges for node/edge counts with teal theme
- Modern footer with teal pulse indicator and gradient overlays
- Staggered reveal animations for graph items

Child Item Priority Fix:
- Change default priority from parent-based (parent - 0.1) to fixed 0.0
- Child items now consistently start at Minimal (0%) priority
- Simplifies priority management and provides clear starting point

Author: Patel230

packages/web/src/components/CreateChildTaskModal.tsx

@@ -76,7 +76,7 @@ export function CreateChildTaskModal({ isOpen, onClose, parentWorkItem }: Create
   const { currentGraph } = useGraph();
   const { showSuccess, showError } = useNotifications();
 
-  const childPriority = Math.max(0, (parentWorkItem.priority || 0.5) - 0.1);
+  const childPriority = 0.0;
 
   const getAssignedToId = (assignedTo: WorkItem['assignedTo']): string => {
     if (!assignedTo) return '';