Kanban Board

# Kanban Board PRD

## Overview
Build an interactive Kanban board for task management.

## Requirements
- Default columns: To Do, In Progress, Done
- Add, edit, and delete cards within any column
- Drag and drop cards between columns
- Drag and drop to reorder cards within a column
- Add and rename columns
- Delete columns (moves cards to "To Do")
- Card fields: title (required), description (optional), color label
- Double-click card to edit
- Persist entire board state to localStorage
- Undo last action (Ctrl+Z)
- Responsive layout — columns scroll horizontally on small screens
- Clean, modern UI with subtle animations on drag

## Tech Stack
- Any frontend framework
- HTML5 Drag and Drop API, or a library (dnd-kit, react-beautiful-dnd, SortableJS)
- No backend required

## Scoring Criteria
- **Functional (40%)**: Drag-and-drop works, CRUD on cards/columns, persistence
- **Quality (20%)**: Smooth animations, no jank, clean code
- **Fidelity (25%)**: All features present, polished look
- **Speed (15%)**: Time bonus