fix(billing): guard workspace suspend against concurrent soft-delete (#22955)

## Context

Follow-up to #22943, addressing the cubic review comments left on that
PR (handled in a follow-up as agreed in the thread).

In `BillingWebhookSubscriptionService.processStripeEvent`, the
suspend/reactivate decision re-reads the workspace and then acts on it.
A concurrent soft-delete landing in that window could transition an
already soft-deleted workspace to `SUSPENDED`, contrary to the
guarded-transition behavior (cubic P2).

## Fix

Added `deletedAt: IsNull()` to the `suspendWorkspace` compare-and-swap
WHERE clause, matching the guard already present in
`reactivateWorkspace`. A concurrent soft-delete now blocks the
suspension instead of transitioning a deleted workspace to `SUSPENDED`.

## On the delete guard (cubic P1)

Cubic also flagged that the `PENDING_CREATION` hard-delete path could
hard-delete a concurrently soft-deleted workspace. On review this is not
worth guarding:

- A `PENDING_CREATION` workspace has no DB schema and no records
(activation is what creates them), so there is no data to lose.
- The cleaner already hard-deletes soft-deleted workspaces by design
(`cleaner.workspace-service.ts` soft-deletes a pending workspace, then
hard-deletes it on a later run), so "hard delete an already soft-deleted
workspace" is a supported transition, not corruption.

So P1 is intentionally left out to keep `deleteWorkspace` and all its
callers unchanged.

## Tests

- `suspendWorkspace` update includes `deletedAt IS NULL` and reports
whether the guarded update applied.

Typecheck, lint, and format pass on the changed files.

packages/twenty-server/src/engine/core-modules/workspace/services/__tests__/workspace.service.spec.ts

@@ -1,7 +1,8 @@
 import { Test, type TestingModule } from '@nestjs/testing';
 import { getDataSourceToken, getRepositoryToken } from '@nestjs/typeorm';
 
-import { type Repository } from 'typeorm';
+import { WorkspaceActivationStatus } from 'twenty-shared/workspace';
+import { IsNull, Not, type Repository } from 'typeorm';
 
 import { BillingSubscriptionService } from 'src/engine/core-modules/billing/services/billing-subscription.service';
 import { BillingService } from 'src/engine/core-modules/billing/services/billing.service';
@@ -57,6 +58,7 @@ describe('WorkspaceService', () => {
             findOne: jest.fn(),
             softDelete: jest.fn(),
             delete: jest.fn(),
+            update: jest.fn(),
             manager: {
               connection: { driver: { options: { type: 'postgres' } } },
             },
@@ -374,4 +376,36 @@ describe('WorkspaceService', () => {
       });
     });
   });
+
+  describe('suspendWorkspace', () => {
+    it('should only suspend workspaces that are not already suspended and not soft-deleted', async () => {
+      jest
+        .spyOn(workspaceRepository, 'update')
+        .mockResolvedValue({ affected: 1 } as never);
+
+      const hasBeenSuspended = await service.suspendWorkspace('workspace-id');
+
+      expect(workspaceRepository.update).toHaveBeenCalledWith(
+        {
+          id: 'workspace-id',
+          activationStatus: Not(WorkspaceActivationStatus.SUSPENDED),
+          deletedAt: IsNull(),
+        },
+        expect.objectContaining({
+          activationStatus: WorkspaceActivationStatus.SUSPENDED,
+        }),
+      );
+      expect(hasBeenSuspended).toBe(true);
+    });
+
+    it('should report no suspension when the guarded update affects no rows', async () => {
+      jest
+        .spyOn(workspaceRepository, 'update')
+        .mockResolvedValue({ affected: 0 } as never);
+
+      const hasBeenSuspended = await service.suspendWorkspace('workspace-id');
+
+      expect(hasBeenSuspended).toBe(false);
+    });
+  });
 });

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

@@ -493,6 +493,7 @@ export class WorkspaceService {
       {
         id,
         activationStatus: Not(WorkspaceActivationStatus.SUSPENDED),
+        deletedAt: IsNull(),
       },
       {
         activationStatus: WorkspaceActivationStatus.SUSPENDED,