Add org Kanban view and popup-based task creation

[AZ0228]

Summary

• Added Kanban drag-and-drop interactions on both task surfaces:
  • Org Task Hub (TasksHub) cards are now draggable between status columns.
  • Event Tasks (EventTasksTab) cards are now draggable between status columns.
• Introduced optimistic status handling so drag/drop reflects immediately in-column while update requests are in flight.
• Added visual drag/drop affordances (dragging card state + active drop-target column styling).
• Kept existing status action buttons in place as fallback controls.

Testing

• cd frontend && NODE_ENV=development npx eslint src/pages/ClubDash/TasksHub/TasksHub.jsx src/pages/ClubDash/EventsManagement/components/EventDashboard/EventTasksTab.jsx (passes)
• cd frontend && npm run build (passes; existing repo-wide warnings remain unrelated)
• Manual verification:
  • Confirmed kanban status action baseline still persists server-side (button move to Done works and remains after refresh).
  • Drag interaction is present and shows immediate visual movement between columns.

Walkthrough artifacts

• Existing modal/kanban walkthrough (previous):
  org_kanban_and_task_create_popups.mp4
• Org kanban status update baseline confirmation:
  Org kanban status change confirmed
• Org kanban drag interaction state:
  Org kanban drag interaction
• Org list status after drag attempt (diagnostic evidence):
  Org list status after drag attempt
• Org kanban after refresh attempt (diagnostic evidence):
  Org kanban after refresh attempt

Notes

• Temporary debug instrumentation added during investigation was removed before finalizing (backend/app.js, TasksHub.jsx, EventTasksTab.jsx).
• Existing unrelated working tree entry backend/events remains untouched.

_{To show artifacts inline, enable in settings.}