Enhance project management views with professional features and consistent UX

- Transform Gantt Chart with professional timeline visualization, zoom controls, and dependency arrows
- Enhance Calendar View with interactive date selection and priority indicators
- Modernize Activity Feed with real-time updates, advanced filtering, and expandable details
- Integrate centralized constants (STATUS_OPTIONS, PRIORITY_OPTIONS, TYPE_OPTIONS) across all views
- Implement consistent colored dropdown filters with icons across all components
- Add unified search functionality with "Search tasks by type, status, priority" placeholder
- Add duplicate name validation to prevent nodes with identical titles
- Organize Gantt Chart controls into two-row layout for better UX
- Fix TypeScript errors and ensure clean compilation
- Standardize dropdown order: Type → Status → Priority across all views

Author: Patel230