feat(billing): cap active users on an owner subscription

Super admin can set a seat limit of 3, 10, 20, or a negotiated number so an owner cannot add users past that cap.

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/src/platform/platform.service.ts

@@ -425,6 +425,30 @@ export class PlatformService {
     return this.storage.usageForOwner(userId, refresh);
   }
 
+  async seatUsage(userId: string) {
+    await this.requireBillingOwner(userId);
+    return this.billing.seatUsage(userId);
+  }
+
+  async setUserCap(userId: string, maxUsers: number) {
+    await this.requireBillingOwner(userId);
+    return this.billing.setMaxUsers(userId, maxUsers);
+  }
+
+  private async requireBillingOwner(userId: string) {
+    const owner = await this.prisma.membership.findFirst({
+      where: { userId, role: 'owner', isActive: true },
+      select: { id: true },
+    });
+    if (!owner) {
+      throw new BadRequestException('سقف کاربر فقط برای مالک محیط معنی دارد');
+    }
+    const account = await this.billing.getByOwnerUserId(userId);
+    if (!account) {
+      throw new BadRequestException('اول برای این مالک یک پلن اعمال کنید');
+    }
+  }
+
   async setStorageQuota(userId: string, quotaGb: number | null) {
     await this.storageUsage(userId, false);
     return this.storage.setQuotaGb(userId, quotaGb);
@@ -495,9 +519,13 @@ export class PlatformService {
         userId: true,
         organizationId: true,
         role: true,
+        isActive: true,
       },
     });
     if (!row) throw new NotFoundException('عضویت پیدا نشد');
+    if (isActive && !row.isActive) {
+      await this.billing.assertSeatAvailable(row.organizationId, row.userId);
+    }
     if (!isActive && row.role === 'owner') {
       const activeOwners = await this.memberships.countActiveOwners(
         row.organizationId,