test(scaffold): add skeleton test files for all 7 API endpoints

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

__tests__/api/tasks.test.ts

@@ -0,0 +1,58 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+vi.mock('@/lib/prisma', () => ({
+  prisma: {
+    task: {
+      findFirst: vi.fn(),
+      update: vi.fn(),
+    },
+  },
+}))
+
+vi.mock('@/lib/api-auth', () => ({
+  authenticateApiRequest: vi.fn(),
+}))
+
+import { prisma } from '@/lib/prisma'
+import { authenticateApiRequest } from '@/lib/api-auth'
+import { PATCH as patchTask } from '@/app/api/tasks/[id]/route'
+
+const mockPrisma = prisma as unknown as {
+  task: { findFirst: ReturnType<typeof vi.fn>; update: ReturnType<typeof vi.fn> }
+}
+const mockAuth = authenticateApiRequest as ReturnType<typeof vi.fn>
+
+function makeRequest(body: unknown, taskId = 'task-1'): [Request, { params: Promise<{ id: string }> }] {
+  return [
+    new Request(`http://localhost/api/tasks/${taskId}`, {
+      method: 'PATCH',
+      headers: { Authorization: 'Bearer test-token', 'Content-Type': 'application/json' },
+      body: JSON.stringify(body),
+    }),
+    { params: Promise.resolve({ id: taskId }) },
+  ]
+}
+
+describe('PATCH /api/tasks/:id', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+  })
+
+  // TC-T-06
+  it.todo('returns 400 for invalid status value')
+
+  // TC-T-07
+  it.todo('returns 400 when body has no recognized fields')
+
+  // TC-T-08
+  it.todo('updates status only and returns 200')
+
+  // TC-T-09
+  it.todo('updates implementation_plan only and returns 200')
+
+  // TC-T-10
+  it.todo('updates both status and implementation_plan and returns 200')
+
+  // TC-T-11
+  it.todo('allows update when user is a team member of the product')
+})