fix(billing): link billing emails to the workspace subdomain (#22401)

## Problem

Billing and workspace-suspension emails hardcoded a
`BILLING_SETTINGS_URL` constant pointing at
`https://app.twenty.com/settings/billing`. A user in
`myworkspace.twenty.com` therefore received a CTA that bounced through
the central `app` domain instead of landing on their own workspace.
Those cross-subdomain redirects are unreliable, so it's better to link
straight to the workspace.

The invite, password-reset and email-verification emails already do this
correctly by building a workspace-specific URL server-side with
`WorkspaceDomainsService.buildWorkspaceURL(...)`; the billing/suspension
senders had the `workspace` entity in scope but never used it.

## Fix

Build the billing settings URL server-side and pass it into the
templates as a `link` prop, mirroring the existing pattern:

- **Templates** now take a `link` prop instead of the hardcoded
constant: `billing-trial-ending`, `billing-trial-converting`,
`billing-subscription-renewing`, `warn-suspended-workspace`.
- **`BillingReminderService`** and **`CleanerWorkspaceService`** build
`buildWorkspaceURL({ workspace, pathname:
getSettingsPath(SettingsPath.Billing) })` and thread it through.
- Wired `WorkspaceDomainsModule` into both NestJS modules; deleted the
now-unused `billing-settings-url.constant.ts`; updated the reminder unit
test.

This also fixes **self-hosted** deployments, which previously got the
same wrong hardcoded `app.twenty.com` link.

### Intentionally unchanged

- `clean-suspended-workspace` keeps its central-domain "start a new
workspace" CTA — that workspace is already deleted, so its subdomain no
longer resolves.
- `password-update-notify` (not a billing email) still uses
`getBaseUrl()`; the workspace entity isn't readily loaded there. Can be
a follow-up.

## Testing

Extended `billing-reminder.service.spec.ts` to assert the
workspace-specific `link` is threaded into the email. Note: local
`typecheck`/tests could not be run because the sandbox proxy repeatedly
dropped `yarn install` mid-fetch; the diff was reviewed line-by-line and
import paths verified against the actual `twenty-shared` exports and
module wiring. CI will provide the authoritative check.

https://claude.ai/code/session_01QsgNd4SWdcRkPFyrnCgj2b

---
_Generated by [Claude
Code](https://claude.ai/code/session_01QsgNd4SWdcRkPFyrnCgj2b)_

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packages/twenty-server/src/engine/workspace-manager/workspace-cleaner/services/cleaner.workspace-service.ts

@@ -8,13 +8,15 @@ import {
   CleanSuspendedWorkspaceEmail,
   WarnSuspendedWorkspaceEmail,
 } from 'twenty-emails';
-import { isDefined } from 'twenty-shared/utils';
+import { SettingsPath } from 'twenty-shared/types';
+import { getSettingsPath, isDefined } from 'twenty-shared/utils';
 import { WorkspaceActivationStatus } from 'twenty-shared/workspace';
 import { In, Repository } from 'typeorm';
 
 import { BillingSubscriptionEntity } from 'src/engine/core-modules/billing/entities/billing-subscription.entity';
 import { SubscriptionStatus } from 'src/engine/core-modules/billing/enums/billing-subscription-status.enum';
 import { BillingSubscriptionService } from 'src/engine/core-modules/billing/services/billing-subscription.service';
+import { WorkspaceDomainsService } from 'src/engine/core-modules/domain/workspace-domains/services/workspace-domains.service';
 import { EmailService } from 'src/engine/core-modules/email/email.service';
 import { I18nService } from 'src/engine/core-modules/i18n/i18n.service';
 import { MetricsService } from 'src/engine/core-modules/metrics/metrics.service';
@@ -67,6 +69,7 @@ export class CleanerWorkspaceService {
     private readonly userWorkspaceRepository: Repository<UserWorkspaceEntity>,
     private readonly i18nService: I18nService,
     private readonly metricsService: MetricsService,
+    private readonly workspaceDomainsService: WorkspaceDomainsService,
   ) {
     this.inactiveDaysBeforeSoftDelete = this.twentyConfigService.get(
       'WORKSPACE_INACTIVE_DAYS_BEFORE_SOFT_DELETION',
@@ -115,6 +118,7 @@ export class CleanerWorkspaceService {
   async sendWarningEmail(
     workspaceMember: WorkspaceMemberWorkspaceEntity,
     workspaceDisplayName: string | undefined,
+    billingSettingsUrl: string,
     daysSinceInactive: number,
   ) {
     const emailData = {
@@ -122,6 +126,7 @@ export class CleanerWorkspaceService {
       inactiveDaysBeforeDelete: this.inactiveDaysBeforeSoftDelete,
       userName: `${workspaceMember.name.firstName} ${workspaceMember.name.lastName}`,
       workspaceDisplayName: `${workspaceDisplayName}`,
+      link: billingSettingsUrl,
       locale: workspaceMember.locale,
     };
     const emailTemplate = WarnSuspendedWorkspaceEmail(emailData);
@@ -177,11 +182,19 @@ export class CleanerWorkspaceService {
         .join(', ')}']`,
     );
 
+    const billingSettingsUrl = this.workspaceDomainsService
+      .buildWorkspaceURL({
+        workspace,
+        pathname: getSettingsPath(SettingsPath.Billing),
+      })
+      .toString();
+
     if (!dryRun) {
       for (const workspaceMember of workspaceMembers) {
         await this.sendWarningEmail(
           workspaceMember,
           workspace.displayName,
+          billingSettingsUrl,
           daysSinceInactive,
         );
 

packages/twenty-server/src/engine/workspace-manager/workspace-cleaner/workspace-cleaner.module.ts

@@ -3,6 +3,7 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 
 import { BillingModule } from 'src/engine/core-modules/billing/billing.module';
 import { BillingSubscriptionEntity } from 'src/engine/core-modules/billing/entities/billing-subscription.entity';
+import { WorkspaceDomainsModule } from 'src/engine/core-modules/domain/workspace-domains/workspace-domains.module';
 import { EmailModule } from 'src/engine/core-modules/email/email.module';
 import { MetricsModule } from 'src/engine/core-modules/metrics/metrics.module';
 import { UserWorkspaceEntity } from 'src/engine/core-modules/user-workspace/user-workspace.entity';
@@ -31,6 +32,7 @@ import { CleanerWorkspaceService } from 'src/engine/workspace-manager/workspace-
     EmailModule,
     BillingModule,
     MetricsModule,
+    WorkspaceDomainsModule,
   ],
   providers: [
     DestroyWorkspaceCommand,