feat: auto-create MemberLunchPick on attendee writes

Adds ensureLunchPickForAttendingMember helper called from confirm,
adminConfirm, and editAttendees attendee-creation paths. No-ops when
the program has no LunchEvent.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

tests/unit/lunch-pick-sync.test.ts

@@ -0,0 +1,99 @@
+import { afterAll, describe, expect, it } from 'vitest'
+import { prisma } from '../setup'
+import {
+  createTestUser,
+  createTestProgram,
+  createTestProject,
+  cleanupTestData,
+  uid,
+} from '../helpers'
+import { ensureLunchPickForAttendingMember } from '@/server/services/lunch-pick-sync'
+
+const programIds: string[] = []
+const userIds: string[] = []
+
+afterAll(async () => {
+  for (const programId of programIds) {
+    await prisma.memberLunchPick.deleteMany({
+      where: { attendingMember: { confirmation: { project: { programId } } } },
+    })
+    await prisma.attendingMember.deleteMany({
+      where: { confirmation: { project: { programId } } },
+    })
+    await prisma.finalistConfirmation.deleteMany({ where: { project: { programId } } })
+    await prisma.lunchEvent.deleteMany({ where: { programId } })
+    await cleanupTestData(programId, [])
+  }
+  if (userIds.length > 0) {
+    await prisma.user.deleteMany({ where: { id: { in: userIds } } })
+  }
+})
+
+async function setupConfirmedAttendee(programId: string) {
+  const user = await createTestUser('APPLICANT')
+  userIds.push(user.id)
+  const project = await createTestProject(programId, {
+    title: `pick-sync-${uid()}`,
+    competitionCategory: 'STARTUP',
+  })
+  const confirmation = await prisma.finalistConfirmation.create({
+    data: {
+      projectId: project.id,
+      category: 'STARTUP',
+      status: 'CONFIRMED',
+      deadline: new Date(Date.now() + 86_400_000),
+      token: `tok-${uid()}`,
+    },
+  })
+  const member = await prisma.attendingMember.create({
+    data: { confirmationId: confirmation.id, userId: user.id },
+  })
+  return member
+}
+
+describe('ensureLunchPickForAttendingMember', () => {
+  it('creates an empty MemberLunchPick when a LunchEvent exists', async () => {
+    const program = await createTestProgram({ name: `lunch-sync-${uid()}` })
+    programIds.push(program.id)
+    await prisma.lunchEvent.create({ data: { programId: program.id } })
+
+    const member = await setupConfirmedAttendee(program.id)
+    await ensureLunchPickForAttendingMember(prisma, member.id)
+
+    const pick = await prisma.memberLunchPick.findUnique({
+      where: { attendingMemberId: member.id },
+    })
+    expect(pick).not.toBeNull()
+    expect(pick?.dishId).toBeNull()
+    expect(pick?.pickedAt).toBeNull()
+  })
+
+  it('is idempotent — calling twice does not create a second pick', async () => {
+    const program = await createTestProgram({ name: `lunch-sync-${uid()}` })
+    programIds.push(program.id)
+    await prisma.lunchEvent.create({ data: { programId: program.id } })
+
+    const member = await setupConfirmedAttendee(program.id)
+    await ensureLunchPickForAttendingMember(prisma, member.id)
+    await ensureLunchPickForAttendingMember(prisma, member.id)
+
+    const picks = await prisma.memberLunchPick.findMany({
+      where: { attendingMemberId: member.id },
+    })
+    expect(picks).toHaveLength(1)
+  })
+
+  it('no-ops when no LunchEvent exists for the program', async () => {
+    const program = await createTestProgram({ name: `lunch-sync-${uid()}` })
+    programIds.push(program.id)
+    // Note: no LunchEvent created.
+
+    const member = await setupConfirmedAttendee(program.id)
+    await ensureLunchPickForAttendingMember(prisma, member.id)
+
+    const pick = await prisma.memberLunchPick.findUnique({
+      where: { attendingMemberId: member.id },
+    })
+    expect(pick).toBeNull()
+  })
+})