feat(billing): replace Stripe trial emails with fair, well-timed reminders (#22186)

## Why

We currently rely on Stripe's automated trial-ending email. It misfires:
the global "remind 7 days before trial ends" setting lands the reminder
on **signup day** for the 7‑day no‑card trial, and the "your card will
be charged" copy makes no sense for a trial with no card. This replaces
it with our own honest, well‑timed, Twenty‑branded emails.

## 🔒 Safety — these emails are OFF by default

Because these reach real customers, the whole feature is gated behind a
kill‑switch that **defaults to `false`**:

- **`BILLING_REMINDER_EMAILS_ENABLED` (default `false`)** — checked
**both** at cron registration **and** on every job run (defense in
depth), so the emails can never be sent inadvertently (not on deploy,
not in staging, not via a stray trigger). They only go out once an
operator explicitly opts in.
- Also gated on `IS_BILLING_ENABLED` (cloud‑only; self‑hosters
unaffected).
- In non‑prod the email driver is typically `logger`, so even if enabled
there, nothing is actually sent.

A unit test asserts that with the switch off, **zero** emails are
produced.

## What it does

A daily cron (`0 8 * * *`) sends three honest, Twenty‑branded emails:

| Plan | Email | When |
|---|---|---|
| No‑card trial (7d) | "Add a card to keep your data" | **1 day before**
trial ends |
| Card‑on‑file trial (30d) | Upcoming‑charge heads‑up (cancel in one
click) | **7 days before** first charge |
| Yearly subscription | Renewal reminder (no surprise) | **7 days
before** each renewal |

- **Monthly renewals get no reminder** (avoids noise) — only the first
charge and annual renewals do.
- Branches no‑card vs with‑card on the customer's payment‑method flag
(with a trial‑duration fallback), so someone who adds a card mid‑trial
correctly gets the charge heads‑up instead of the add‑a‑card one.
- **Idempotent** per `(workspace, boundary date)` via workspace‑level
user vars — yearly reminders re‑fire each period, but the daily cron
never double‑sends.
- Offsets are configurable via new `BILLING_*_REMINDER_DAYS_BEFORE`
variables.

Also **warms up the tone** of the existing suspended / deleted workspace
emails (less robotic, fair, loss‑aversion framing) — these already act
as the "come back or lose your data" win‑back, so no extra win‑back
email was added.

## Rollout

1. Merge.
2. Disable Stripe's automated trial/renewal customer emails in the
Stripe dashboard.
3. Review copy/timing, then set `BILLING_REMINDER_EMAILS_ENABLED=true`
to turn the cron on.

## Notes for reviewers

- **i18n:** new English strings render via Lingui's msgid fallback;
translation catalogs are intentionally **not** included to keep the diff
focused (the repo extracts translations via its standard periodic
`lingui extract` sync — `main` already carries catalog drift). Diff is
18 code files.
- **Recipients:** reminders go to all workspace members, consistent with
the existing suspension emails. Happy to scope the charge‑related ones
to billing admins if preferred.
- **Follow‑ups discussed:** in‑app trial banner, loss‑aversion with real
record counts, and failed‑payment dunning are the higher‑leverage
conversion levers beyond this.

## Test plan

- [x] `typecheck` (twenty-server, twenty-emails)
- [x] oxlint type‑aware + oxfmt
- [x] Unit tests: no‑card path, with‑card path, idempotency, yearly
renewal, billing‑disabled, **kill‑switch off → no send** (6/6 green)
- [ ] Manual: set the flag on a staging instance with `logger` driver
and confirm the right email is logged at each boundary

https://claude.ai/code/session_0147ujzHv1X4vzimf4iGbnT4

---
_Generated by [Claude
Code](https://claude.ai/code/session_0147ujzHv1X4vzimf4iGbnT4)_

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packages/twenty-server/src/database/commands/cron-register-all.command.ts

@@ -6,6 +6,7 @@ import { isDefined } from 'twenty-shared/utils';
 import { MarketplaceCatalogSyncCronCommand } from 'src/engine/core-modules/application/application-marketplace/crons/commands/marketplace-catalog-sync.cron.command';
 import { StaleRegistrationCleanupCronCommand } from 'src/engine/core-modules/application/application-oauth/stale-registration-cleanup/commands/stale-registration-cleanup.cron.command';
 import { ApplicationVersionCheckCronCommand } from 'src/engine/core-modules/application/application-upgrade/crons/commands/application-version-check.cron.command';
+import { BillingReminderCronCommand } from 'src/engine/core-modules/billing/reminders/crons/commands/billing-reminder.cron.command';
 import { EnterpriseKeyValidationCronCommand } from 'src/engine/core-modules/enterprise/cron/command/enterprise-key-validation.cron.command';
 import { EventLogCleanupCronCommand } from 'src/engine/core-modules/event-logs/cleanup/commands/event-log-cleanup.cron.command';
 import { RotateSigningKeysCronCommand } from 'src/engine/core-modules/jwt/crons/commands/rotate-signing-keys.cron.command';
@@ -64,6 +65,7 @@ export class CronRegisterAllCommand extends CommandRunner {
     private readonly marketplaceCatalogSyncCronCommand: MarketplaceCatalogSyncCronCommand,
     private readonly applicationVersionCheckCronCommand: ApplicationVersionCheckCronCommand,
     private readonly staleRegistrationCleanupCronCommand: StaleRegistrationCleanupCronCommand,
+    private readonly billingReminderCronCommand: BillingReminderCronCommand,
     private readonly twentyConfigService: TwentyConfigService,
   ) {
     super();
@@ -80,6 +82,8 @@ export class CronRegisterAllCommand extends CommandRunner {
       'MARKETPLACE_CATALOG_SYNC_CRON_ENABLED',
     );
 
+    const isBillingEnabled = this.twentyConfigService.get('IS_BILLING_ENABLED');
+
     const allCommands = [
       {
         name: 'MessagingMessagesImport',
@@ -179,6 +183,11 @@ export class CronRegisterAllCommand extends CommandRunner {
         name: 'StaleRegistrationCleanup',
         command: this.staleRegistrationCleanupCronCommand,
       },
+      {
+        name: 'BillingReminder',
+        command: this.billingReminderCronCommand,
+        isEnabled: isBillingEnabled,
+      },
     ];
 
     let successCount = 0;

packages/twenty-server/src/database/commands/database-command.module.ts

@@ -22,6 +22,7 @@ import { StaleRegistrationCleanupModule } from 'src/engine/core-modules/applicat
 import { ApplicationUpgradeModule } from 'src/engine/core-modules/application/application-upgrade/application-upgrade.module';
 import { ApplicationModule } from 'src/engine/core-modules/application/application.module';
 import { PreInstalledAppsModule } from 'src/engine/core-modules/application/pre-installed-apps/pre-installed-apps.module';
+import { BillingReminderModule } from 'src/engine/core-modules/billing/reminders/billing-reminder.module';
 import { EnterpriseKeyValidationCronCommand } from 'src/engine/core-modules/enterprise/cron/command/enterprise-key-validation.cron.command';
 import { EnterpriseModule } from 'src/engine/core-modules/enterprise/enterprise.module';
 import { EventLogCleanupModule } from 'src/engine/core-modules/event-logs/cleanup/event-log-cleanup.module';
@@ -76,6 +77,7 @@ import { AutomatedTriggerModule } from 'src/modules/workflow/workflow-trigger/au
     WorkspaceCleanerModule,
     WorkspaceMigrationModule,
     TrashCleanupModule,
+    BillingReminderModule,
     CodeInterpreterSessionCleanupModule,
     PublicDomainModule,
     EventLogCleanupModule,