feat(billing): start demos on the core plan and apply tariff levels

New signups get the core module set with the 7-day demo. Superadmin can apply core, team, organization, or dedicated and the owner's environments take that level's access.

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

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

@@ -9,6 +9,7 @@ import type {
   PlatformOrganizationDto,
   PlatformStatsDto,
   PlatformUserDto,
+  ProductPlanCode,
   UserRole,
 } from '@mento/shared';
 import { isBusinessField } from '@mento/shared';
@@ -472,6 +473,16 @@ export class PlatformService {
     return this.getUser(userId);
   }
 
+  async applyProductPlan(id: string, planCode: ProductPlanCode) {
+    const existing = await this.prisma.organization.findUnique({
+      where: { id },
+      select: { id: true },
+    });
+    if (!existing) throw new NotFoundException('محیط پیدا نشد');
+    await this.billing.applyProductPlan(id, planCode);
+    return this.getOrganization(id);
+  }
+
   async updateOrganizationModules(id: string, dto: UpdateOrgModulesDto) {
     const existing = await this.prisma.organization.findUnique({
       where: { id },