Create billing customer at signup so onboarding rewards are credited (#22633)

## Problem

Onboarding credit rewards (install apps, import contacts, invite team)
were silently dropped. They credit the workspace balance via
`billingCustomer.increment(...)`, but no `billingCustomer` row exists
until the plan step (it's created lazily when the first subscription is
set up, which is after those steps). So the increment affected 0 rows
and the credit was lost. A user installing 3 apps saw only the trial
grant, not the expected +1.5 credits.

## Fix

Create the Stripe customer + `billingCustomer` row eagerly at signup via
a new `BillingCreditService.ensureBillingCustomer`, called from
`signUpOnNewWorkspace` after the workspace transaction commits. It is
idempotent, guarded by `IS_BILLING_ENABLED`, and non-blocking (failures
are logged, not thrown). The later subscription flow reuses this
customer (no duplicate Stripe customer), and trial eligibility is
unchanged since the customer has no subscriptions yet.

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packages/twenty-server/src/engine/core-modules/auth/services/sign-in-up.service.spec.ts

@@ -108,6 +108,9 @@ const createSignInUpServiceForTests = () => {
     {
       creditWorkspaceBalance: jest.fn(),
     } as any,
+    {
+      isBillingEnabled: jest.fn(),
+    } as any,
     {
       createQueryRunner: jest.fn(() => queryRunnerMock),
     } as any,

packages/twenty-server/src/engine/core-modules/auth/services/sign-in-up.service.ts

@@ -25,6 +25,7 @@ import {
 } from 'src/engine/core-modules/app-token/app-token.entity';
 import { ApplicationService } from 'src/engine/core-modules/application/application.service';
 import { BillingCreditService } from 'src/engine/core-modules/billing/services/billing-credit.service';
+import { BillingService } from 'src/engine/core-modules/billing/services/billing.service';
 import {
   AuthException,
   AuthExceptionCode,
@@ -93,6 +94,7 @@ export class SignInUpService {
     private readonly enterprisePlanService: EnterprisePlanService,
     private readonly eventLogEmitterService: EventLogEmitterService,
     private readonly billingCreditService: BillingCreditService,
+    private readonly billingService: BillingService,
     @InjectDataSource()
     private readonly dataSource: DataSource,
   ) {}
@@ -708,6 +710,14 @@ export class SignInUpService {
         .createContext({ workspaceId })
         .insertWorkspaceEvent(WORKSPACE_CREATED_EVENT, {});
 
+      if (this.billingService.isBillingEnabled()) {
+        await this.billingService.ensureBillingCustomer({
+          userEmail: email,
+          workspaceId: workspace.id,
+          workspaceDisplayName: workspace.displayName,
+        });
+      }
+
       return { user, workspace };
     } catch (error) {
       const isSubdomainConflict =

packages/twenty-server/src/engine/core-modules/billing/services/__test__/billing.service.spec.ts

@@ -0,0 +1,94 @@
+/* @license Enterprise */
+
+import { Test, type TestingModule } from '@nestjs/testing';
+
+import { BillingCustomerEntity } from 'src/engine/core-modules/billing/entities/billing-customer.entity';
+import { BillingSubscriptionEntity } from 'src/engine/core-modules/billing/entities/billing-subscription.entity';
+import { BillingProductService } from 'src/engine/core-modules/billing/services/billing-product.service';
+import { BillingSubscriptionService } from 'src/engine/core-modules/billing/services/billing-subscription.service';
+import { BillingService } from 'src/engine/core-modules/billing/services/billing.service';
+import { StripeCustomerService } from 'src/engine/core-modules/billing/stripe/services/stripe-customer.service';
+import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
+import { getWorkspaceScopedRepositoryToken } from 'src/engine/twenty-orm/workspace-scoped-repository/get-workspace-scoped-repository-token.util';
+
+describe('BillingService', () => {
+  let service: BillingService;
+  let stripeCustomerService: jest.Mocked<
+    Pick<StripeCustomerService, 'createStripeCustomer'>
+  >;
+  let billingCustomerRepository: jest.Mocked<{ findOne: jest.Mock }>;
+
+  const ensureParams = {
+    userEmail: 'user@example.com',
+    workspaceId: 'ws_123',
+    workspaceDisplayName: 'Acme',
+  };
+
+  beforeEach(async () => {
+    const module: TestingModule = await Test.createTestingModule({
+      providers: [
+        BillingService,
+        {
+          provide: TwentyConfigService,
+          useValue: { get: jest.fn() },
+        },
+        {
+          provide: BillingSubscriptionService,
+          useValue: {},
+        },
+        {
+          provide: BillingProductService,
+          useValue: {},
+        },
+        {
+          provide: StripeCustomerService,
+          useValue: {
+            createStripeCustomer: jest
+              .fn()
+              .mockResolvedValue({ id: 'cus_123' }),
+          },
+        },
+        {
+          provide: getWorkspaceScopedRepositoryToken(BillingSubscriptionEntity),
+          useValue: { findOne: jest.fn() },
+        },
+        {
+          provide: getWorkspaceScopedRepositoryToken(BillingCustomerEntity),
+          useValue: { findOne: jest.fn().mockResolvedValue(null) },
+        },
+      ],
+    }).compile();
+
+    service = module.get<BillingService>(BillingService);
+    stripeCustomerService = module.get(StripeCustomerService);
+    billingCustomerRepository = module.get(
+      getWorkspaceScopedRepositoryToken(BillingCustomerEntity),
+    );
+  });
+
+  afterEach(() => {
+    jest.clearAllMocks();
+  });
+
+  describe('ensureBillingCustomer', () => {
+    it('creates a stripe customer when none exists', async () => {
+      billingCustomerRepository.findOne.mockResolvedValue(null);
+
+      await service.ensureBillingCustomer(ensureParams);
+
+      expect(stripeCustomerService.createStripeCustomer).toHaveBeenCalledWith(
+        'user@example.com',
+        'ws_123',
+        'Acme',
+      );
+    });
+
+    it('is idempotent when a billing customer already exists', async () => {
+      billingCustomerRepository.findOne.mockResolvedValue({ id: 'bc_1' });
+
+      await service.ensureBillingCustomer(ensureParams);
+
+      expect(stripeCustomerService.createStripeCustomer).not.toHaveBeenCalled();
+    });
+  });
+});

packages/twenty-server/src/engine/core-modules/billing/services/billing.service.ts

@@ -4,10 +4,12 @@ import { Injectable, Logger } from '@nestjs/common';
 
 import { isDefined } from 'twenty-shared/utils';
 
+import { BillingCustomerEntity } from 'src/engine/core-modules/billing/entities/billing-customer.entity';
 import { BillingSubscriptionEntity } from 'src/engine/core-modules/billing/entities/billing-subscription.entity';
 import { type BillingEntitlementKey } from 'src/engine/core-modules/billing/enums/billing-entitlement-key.enum';
 import { BillingProductService } from 'src/engine/core-modules/billing/services/billing-product.service';
 import { BillingSubscriptionService } from 'src/engine/core-modules/billing/services/billing-subscription.service';
+import { StripeCustomerService } from 'src/engine/core-modules/billing/stripe/services/stripe-customer.service';
 import { TwentyConfigService } from 'src/engine/core-modules/twenty-config/twenty-config.service';
 import { InjectWorkspaceScopedRepository } from 'src/engine/twenty-orm/workspace-scoped-repository/inject-workspace-scoped-repository.decorator';
 import { WorkspaceScopedRepository } from 'src/engine/twenty-orm/workspace-scoped-repository/workspace-scoped-repository';
@@ -18,14 +20,40 @@ export class BillingService {
     private readonly twentyConfigService: TwentyConfigService,
     private readonly billingSubscriptionService: BillingSubscriptionService,
     private readonly billingProductService: BillingProductService,
+    private readonly stripeCustomerService: StripeCustomerService,
     @InjectWorkspaceScopedRepository(BillingSubscriptionEntity)
     private readonly billingSubscriptionRepository: WorkspaceScopedRepository<BillingSubscriptionEntity>,
+    @InjectWorkspaceScopedRepository(BillingCustomerEntity)
+    private readonly billingCustomerRepository: WorkspaceScopedRepository<BillingCustomerEntity>,
   ) {}
 
   isBillingEnabled() {
     return this.twentyConfigService.get('IS_BILLING_ENABLED');
   }
 
+  async ensureBillingCustomer({
+    userEmail,
+    workspaceId,
+    workspaceDisplayName,
+  }: {
+    userEmail: string;
+    workspaceId: string;
+    workspaceDisplayName: string | undefined;
+  }): Promise<void> {
+    const existingBillingCustomer =
+      await this.billingCustomerRepository.findOne(workspaceId, { where: {} });
+
+    if (isDefined(existingBillingCustomer)) {
+      return;
+    }
+
+    await this.stripeCustomerService.createStripeCustomer(
+      userEmail,
+      workspaceId,
+      workspaceDisplayName,
+    );
+  }
+
   async hasWorkspaceAnySubscription(workspaceId: string) {
     const isBillingEnabled = this.isBillingEnabled();