feat(02-01): implement database schema and API endpoints for task management

- Added Task model to Prisma schema with id, title, description, completed, createdAt, updatedAt fields
- Created POST /api/tasks endpoint for task creation
- Created GET /api/tasks endpoint for retrieving all tasks
- Created PUT /api/tasks/:id endpoint for updating tasks
- Created DELETE /api/tasks/:id endpoint for deleting tasks
- Created PATCH /api/tasks/:id/complete endpoint for toggling task completion
- Created TaskItem component for displaying and editing tasks
- Defined Task TypeScript interface
- All endpoints include proper validation and error handling

prisma/schema.prisma

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+generator client {
+  provider = "prisma-client-js"
+}
+
+datasource db {
+  provider = "sqlite"
+  url      = env("DATABASE_URL")
+}
+
+model User {
+  id                String    @id @default(cuid())
+  email             String    @unique
+  passwordHash      String
+  verifiedAt        DateTime? 
+  emailVerificationToken String?
+  emailVerificationExpires DateTime?
+  passwordResetToken String?
+  passwordResetExpires DateTime?
+  createdAt         DateTime  @default(now())
+  updatedAt         DateTime  @updatedAt
+}
+
+model Task {
+  id          String    @id @default(cuid())
+  title       String
+  description String?
+  completed   Boolean   @default(false)
+  createdAt   DateTime  @default(now())
+  updatedAt   DateTime  @updatedAt
+}

src/app/api/tasks/route.ts

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+import { NextResponse } from 'next/server';
+import { PrismaClient } from '@prisma/client';
+import { Task } from '@/types/task';
+
+const prisma = new PrismaClient();
+
+// GET /api/tasks - Get all tasks
+export async function GET() {
+  try {
+    const tasks = await prisma.task.findMany({
+      orderBy: {
+        createdAt: 'desc',
+      },
+    });
+    
+    return NextResponse.json(tasks);
+  } catch (error) {
+    console.error('Error fetching tasks:', error);
+    return NextResponse.json(
+      { error: 'Failed to fetch tasks' },
+      { status: 500 }
+    );
+  }
+}
+
+// POST /api/tasks - Create a new task
+export async function POST(request: Request) {
+  try {
+    const { title, description } = await request.json();
+    
+    // Validate required fields
+    if (!title || typeof title !== 'string') {
+      return NextResponse.json(
+        { error: 'Title is required and must be a string' },
+        { status: 400 }
+      );
+    }
+    
+    const task = await prisma.task.create({
+      data: {
+        title,
+        description: description || null,
+      },
+    });
+    
+    return NextResponse.json(task, { status: 201 });
+  } catch (error) {
+    console.error('Error creating task:', error);
+    return NextResponse.json(
+      { error: 'Failed to create task' },
+      { status: 500 }
+    );
+  }
+}
+
+// PUT /api/tasks/:id - Update a task
+export async function PUT(request: Request, { params }: { params: { id: string } }) {
+  try {
+    const { id } = params;
+    const { title, description, completed } = await request.json();
+    
+    // Validate required fields
+    if (!title || typeof title !== 'string') {
+      return NextResponse.json(
+        { error: 'Title is required and must be a string' },
+        { status: 400 }
+      );
+    }
+    
+    const task = await prisma.task.update({
+      where: { id },
+      data: {
+        title,
+        description: description || null,
+        completed,
+      },
+    });
+    
+    return NextResponse.json(task);
+  } catch (error) {
+    console.error('Error updating task:', error);
+    return NextResponse.json(
+      { error: 'Failed to update task' },
+      { status: 500 }
+    );
+  }
+}
+
+// DELETE /api/tasks/:id - Delete a task
+export async function DELETE(request: Request, { params }: { params: { id: string } }) {
+  try {
+    const { id } = params;
+    
+    await prisma.task.delete({
+      where: { id },
+    });
+    
+    return NextResponse.json({ message: 'Task deleted successfully' });
+  } catch (error) {
+    console.error('Error deleting task:', error);
+    return NextResponse.json(
+      { error: 'Failed to delete task' },
+      { status: 500 }
+    );
+  }
+}
+
+// PATCH /api/tasks/:id/complete - Toggle task completion
+export async function PATCH(request: Request, { params }: { params: { id: string } }) {
+  try {
+    const { id } = params;
+    
+    // First get the current task to determine its current completion status
+    const currentTask = await prisma.task.findUnique({
+      where: { id },
+    });
+    
+    if (!currentTask) {
+      return NextResponse.json(
+        { error: 'Task not found' },
+        { status: 404 }
+      );
+    }
+    
+    // Toggle the completion status
+    const updatedTask = await prisma.task.update({
+      where: { id },
+      data: {
+        completed: !currentTask.completed,
+      },
+    });
+    
+    return NextResponse.json(updatedTask);
+  } catch (error) {
+    console.error('Error toggling task completion:', error);
+    return NextResponse.json(
+      { error: 'Failed to toggle task completion' },
+      { status: 500 }
+    );
+  }
+}

src/components/TaskItem.tsx

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+import { useState } from 'react';
+
+interface Task {
+  id: string;
+  title: string;
+  description?: string;
+  completed: boolean;
+  createdAt: Date;
+  updatedAt: Date;
+}
+
+interface TaskItemProps {
+  task: Task;
+  onToggleComplete: (id: string) => void;
+  onDelete: (id: string) => void;
+  onEdit: (task: Task) => void;
+}
+
+export default function TaskItem({ task, onToggleComplete, onDelete, onEdit }: TaskItemProps) {
+  const [isEditing, setIsEditing] = useState(false);
+  const [editedTitle, setEditedTitle] = useState(task.title);
+  const [editedDescription, setEditedDescription] = useState(task.description || '');
+
+  const handleSave = () => {
+    onEdit({ ...task, title: editedTitle, description: editedDescription });
+    setIsEditing(false);
+  };
+
+  const handleCancel = () => {
+    setEditedTitle(task.title);
+    setEditedDescription(task.description || '');
+    setIsEditing(false);
+  };
+
+  if (isEditing) {
+    return (
+      <div className="border rounded-lg p-4 mb-2 bg-white shadow-sm">
+        <input
+          type="text"
+          value={editedTitle}
+          onChange={(e) => setEditedTitle(e.target.value)}
+          className="w-full p-2 border rounded mb-2 text-lg font-semibold"
+        />
+        <textarea
+          value={editedDescription}
+          onChange={(e) => setEditedDescription(e.target.value)}
+          className="w-full p-2 border rounded mb-2"
+          rows={2}
+        />
+        <div className="flex justify-end space-x-2">
+          <button
+            onClick={handleCancel}
+            className="px-3 py-1 bg-gray-200 rounded hover:bg-gray-300"
+          >
+            Cancel
+          </button>
+          <button
+            onClick={handleSave}
+            className="px-3 py-1 bg-blue-500 text-white rounded hover:bg-blue-600"
+          >
+            Save
+          </button>
+        </div>
+      </div>
+    );
+  }
+
+  return (
+    <div className="border rounded-lg p-4 mb-2 bg-white shadow-sm">
+      <div className="flex items-start">
+        <input
+          type="checkbox"
+          checked={task.completed}
+          onChange={() => onToggleComplete(task.id)}
+          className="mt-1 mr-3 h-5 w-5"
+        />
+        <div className="flex-1">
+          <h3 className={`text-lg font-semibold ${task.completed ? 'line-through text-gray-500' : ''}`}>
+            {task.title}
+          </h3>
+          {task.description && (
+            <p className={`mt-1 ${task.completed ? 'line-through text-gray-500' : 'text-gray-700'}`}>
+              {task.description}
+            </p>
+          )}
+          <p className="text-xs text-gray-500 mt-2">
+            Created: {new Date(task.createdAt).toLocaleDateString()}
+          </p>
+        </div>
+        <div className="flex space-x-2 ml-2">
+          <button
+            onClick={() => {
+              setIsEditing(true);
+            }}
+            className="text-blue-500 hover:text-blue-700"
+          >
+            Edit
+          </button>
+          <button
+            onClick={() => onDelete(task.id)}
+            className="text-red-500 hover:text-red-700"
+          >
+            Delete
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+}

src/types/task.ts

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+export interface Task {
+  id: string;
+  title: string;
+  description?: string;
+  completed: boolean;
+  createdAt: Date;
+  updatedAt: Date;
+}