fix(mentor): defer in-app-notification emails when mentoring round is draft

Mentor-assignment flows (mentor.assign, autoAssign, bulkAssign,
bulkAutoAssign, autoAssignBulkForRound) call createNotification and
notifyProjectTeam for MENTEE_ASSIGNED / MENTOR_ASSIGNED. Both
notification types have NotificationEmailSetting.sendEmail = true, so
the notification system fires its own styled email in addition to the
explicit mentor-team / coalesced emails on the same code path. The
earlier defer-emails-until-round-open fix only gated the explicit
sendMentorBulkAssignmentEmail / sendMentorTeamAssignmentEmail calls;
this parallel email path kept firing immediately at every assignment.

Result on prod 2026-05-26: Camille Lopez (assigned to 9 projects via
two bulk_assigns) received 7 emails at 15:04 + 1 at 15:32 from the
notification-system path during draft, plus 1 coalesced email at the
18:20 round activation = 9 sends instead of 1. Every PEARL team
member (and equivalents on other teams) received 3 emails for the
same reason.

Fix
- Add `skipEmail?: boolean` to CreateNotificationParams,
  createNotification, createBulkNotifications, and (via spread)
  notifyProjectTeam. When true the in-app notification row still
  fires but the parallel email send is suppressed; the coalesced
  mentor email and team intro at activateRound time remain the
  single source of email truth.
- Wire it up in every mentor-assignment site: compute the existing
  shouldDeferEmailsForProject gate once before the createNotification
  / notifyProjectTeam calls and pass `skipEmail: deferThisEmail`.
  bulkAssign precomputes draftProjectIds for the whole batch.
  autoAssignBulkForRound uses the round's status directly.
- New regression suite (mentor-email-deferral.test.ts, 3 cases):
  vi.mocks @/lib/email, asserts zero outbound sends when round is
  ROUND_DRAFT, confirms in-app notification rows still get written,
  and re-verifies the ACTIVE-round path still emails.

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

tests/unit/mentor-email-deferral.test.ts

@@ -0,0 +1,228 @@
+/**
+ * Regression: mentor-assignment emails must be deferred while the
+ * project's MENTORING round is still ROUND_DRAFT. The earlier fix only
+ * deferred the explicit `sendMentorBulkAssignmentEmail` path; the parallel
+ * in-app-notification → email path (MENTEE_ASSIGNED, MENTOR_ASSIGNED) kept
+ * firing immediately, causing duplicate sends both at assign-time AND
+ * again when activateRound coalesced the same assignments. Verified
+ * against prod incident 2026-05-26 (Camille Lopez received 9 emails).
+ *
+ * These tests assert that:
+ *   - in DRAFT: in-app notifications still create rows, but the styled
+ *     notification email is NOT sent;
+ *   - in ACTIVE: the styled notification email IS sent (legacy behaviour
+ *     preserved when the round is open).
+ */
+
+import { afterAll, beforeEach, describe, expect, it, vi } from 'vitest'
+import { prisma, createCaller } from '../setup'
+import {
+  createTestUser,
+  createTestProgram,
+  createTestProject,
+  cleanupTestData,
+  uid,
+} from '../helpers'
+import { mentorRouter } from '../../src/server/routers/mentor'
+import type { UserRole } from '@prisma/client'
+
+vi.mock('@/lib/email', async () => {
+  const actual = await vi.importActual<typeof import('@/lib/email')>('@/lib/email')
+  return {
+    ...actual,
+    sendStyledNotificationEmail: vi.fn(async () => undefined),
+    sendMentorTeamAssignmentEmail: vi.fn(async () => undefined),
+    sendMentorBulkAssignmentEmail: vi.fn(async () => undefined),
+    sendTeamMentorIntroductionEmail: vi.fn(async () => undefined),
+  }
+})
+
+const email = await import('@/lib/email')
+const sendStyledMock = email.sendStyledNotificationEmail as ReturnType<typeof vi.fn>
+const sendMentorBulkMock = email.sendMentorBulkAssignmentEmail as ReturnType<typeof vi.fn>
+const sendTeamIntroMock = email.sendTeamMentorIntroductionEmail as ReturnType<typeof vi.fn>
+
+async function makeMentor(): Promise<{ id: string; email: string }> {
+  const id = uid('mentor')
+  const u = await prisma.user.create({
+    data: {
+      id,
+      email: `${id}@test.local`,
+      name: `Mentor ${id}`,
+      role: 'MENTOR' as UserRole,
+      roles: ['MENTOR'] as UserRole[],
+      status: 'ACTIVE',
+      // Email path requires the user to opt into emails. Default for new test
+      // users is EMAIL so styled-email sends fire when the gate is open.
+      notificationPreference: 'EMAIL',
+    },
+  })
+  return { id: u.id, email: u.email }
+}
+
+async function makeTeamMember(projectId: string): Promise<string> {
+  const id = uid('teamuser')
+  const u = await prisma.user.create({
+    data: {
+      id,
+      email: `${id}@test.local`,
+      name: `Team ${id}`,
+      role: 'APPLICANT' as UserRole,
+      roles: ['APPLICANT'] as UserRole[],
+      status: 'ACTIVE',
+      notificationPreference: 'EMAIL',
+    },
+  })
+  await prisma.teamMember.create({
+    data: { projectId, userId: u.id, role: 'MEMBER' },
+  })
+  return u.id
+}
+
+async function attachToMentoringRound(
+  programId: string,
+  projectId: string,
+  status: 'ROUND_DRAFT' | 'ROUND_ACTIVE',
+): Promise<string> {
+  const slug = uid()
+  const competition = await prisma.competition.create({
+    data: {
+      name: `Comp ${slug}`,
+      slug: `comp-${slug}`,
+      programId,
+      status: 'ACTIVE',
+    },
+  })
+  const round = await prisma.round.create({
+    data: {
+      name: `Mentoring ${slug}`,
+      slug: `mentoring-${slug}`,
+      roundType: 'MENTORING',
+      sortOrder: 1,
+      status,
+      competitionId: competition.id,
+    },
+  })
+  await prisma.projectRoundState.create({
+    data: { roundId: round.id, projectId },
+  })
+  return round.id
+}
+
+describe('mentor-assignment email deferral (regression for 2026-05-26 duplicate-email incident)', () => {
+  const programIds: string[] = []
+  const userIds: string[] = []
+
+  beforeEach(() => {
+    sendStyledMock.mockClear()
+    sendMentorBulkMock.mockClear()
+    sendTeamIntroMock.mockClear()
+  })
+
+  afterAll(async () => {
+    for (const programId of programIds) {
+      await prisma.mentorAssignment.deleteMany({ where: { project: { programId } } })
+      await prisma.teamMember.deleteMany({ where: { project: { programId } } })
+      await cleanupTestData(programId, [])
+    }
+    if (userIds.length > 0) {
+      await prisma.user.deleteMany({ where: { id: { in: userIds } } })
+    }
+  })
+
+  it('mentor.assign in DRAFT round creates in-app notif rows but sends ZERO emails', async () => {
+    const admin = await createTestUser('SUPER_ADMIN')
+    userIds.push(admin.id)
+    const program = await createTestProgram({ name: `defer-draft-${uid()}` })
+    programIds.push(program.id)
+    const project = await createTestProject(program.id, { title: 'Draft Project' })
+    await attachToMentoringRound(program.id, project.id, 'ROUND_DRAFT')
+
+    const mentor = await makeMentor()
+    userIds.push(mentor.id)
+    const teamUser = await makeTeamMember(project.id)
+    userIds.push(teamUser)
+
+    const caller = createCaller(mentorRouter, {
+      id: admin.id,
+      email: admin.email,
+      role: 'SUPER_ADMIN',
+    })
+    await caller.assign({ projectId: project.id, mentorId: mentor.id })
+
+    expect(sendStyledMock).not.toHaveBeenCalled()
+    expect(sendMentorBulkMock).not.toHaveBeenCalled()
+    expect(sendTeamIntroMock).not.toHaveBeenCalled()
+
+    // In-app notification rows still fire so admin + mentor see staged state.
+    const mentorNotifs = await prisma.inAppNotification.findMany({
+      where: { userId: mentor.id, type: 'MENTEE_ASSIGNED' },
+    })
+    expect(mentorNotifs.length).toBe(1)
+    const teamNotifs = await prisma.inAppNotification.findMany({
+      where: { userId: teamUser, type: 'MENTOR_ASSIGNED' },
+    })
+    expect(teamNotifs.length).toBe(1)
+  })
+
+  it('mentor.assign in ACTIVE round still sends the per-assignment emails (legacy behaviour preserved)', async () => {
+    const admin = await createTestUser('SUPER_ADMIN')
+    userIds.push(admin.id)
+    const program = await createTestProgram({ name: `defer-active-${uid()}` })
+    programIds.push(program.id)
+    const project = await createTestProject(program.id, { title: 'Active Project' })
+    await attachToMentoringRound(program.id, project.id, 'ROUND_ACTIVE')
+
+    const mentor = await makeMentor()
+    userIds.push(mentor.id)
+    const teamUser = await makeTeamMember(project.id)
+    userIds.push(teamUser)
+
+    const caller = createCaller(mentorRouter, {
+      id: admin.id,
+      email: admin.email,
+      role: 'SUPER_ADMIN',
+    })
+    await caller.assign({ projectId: project.id, mentorId: mentor.id })
+
+    // Either styled notif email OR the explicit team-intro email is allowed
+    // to fire here — point is: at least one outbound email happens when the
+    // round is open. The DRAFT test above is the one that must stay at zero.
+    const sentCount =
+      sendStyledMock.mock.calls.length + sendTeamIntroMock.mock.calls.length
+    expect(sentCount).toBeGreaterThan(0)
+  })
+
+  it('mentor.bulkAssign in DRAFT round sends ZERO emails across multiple projects', async () => {
+    const admin = await createTestUser('SUPER_ADMIN')
+    userIds.push(admin.id)
+    const program = await createTestProgram({ name: `defer-bulk-${uid()}` })
+    programIds.push(program.id)
+    const p1 = await createTestProject(program.id, { title: 'BulkDraft 1' })
+    const p2 = await createTestProject(program.id, { title: 'BulkDraft 2' })
+    const p3 = await createTestProject(program.id, { title: 'BulkDraft 3' })
+    await attachToMentoringRound(program.id, p1.id, 'ROUND_DRAFT')
+    await attachToMentoringRound(program.id, p2.id, 'ROUND_DRAFT')
+    await attachToMentoringRound(program.id, p3.id, 'ROUND_DRAFT')
+
+    const mentor = await makeMentor()
+    userIds.push(mentor.id)
+    userIds.push(await makeTeamMember(p1.id))
+    userIds.push(await makeTeamMember(p2.id))
+    userIds.push(await makeTeamMember(p3.id))
+
+    const caller = createCaller(mentorRouter, {
+      id: admin.id,
+      email: admin.email,
+      role: 'SUPER_ADMIN',
+    })
+    await caller.bulkAssign({
+      mentorIds: [mentor.id],
+      projectIds: [p1.id, p2.id, p3.id],
+    })
+
+    expect(sendStyledMock).not.toHaveBeenCalled()
+    expect(sendMentorBulkMock).not.toHaveBeenCalled()
+    expect(sendTeamIntroMock).not.toHaveBeenCalled()
+  })
+})