feat: add custom domain support with SSL, DNS verification, and billing

Users can assign a custom domain to their app with automatic SSL via
cert-manager. Includes DNS verification flow (CNAME check), Persian
instructions, admin-configurable pricing via PlatformSetting, and
integration into the deploy wizard cost calculation.

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

backend/src/billing/billing.service.ts

@@ -5,6 +5,7 @@ import { ServicePlan } from './entities/service-plan.entity';
 import { PricingRule } from './entities/pricing-rule.entity';
 import { Wallet } from './entities/wallet.entity';
 import { WalletTransaction } from './entities/wallet-transaction.entity';
+import { PlatformSetting } from './entities/platform-setting.entity';
 import { TransactionType, BillingCycle, PricingResourceType } from '../common/enums';
 import {
   CreateServicePlanDto,
@@ -23,6 +24,7 @@ export class BillingService {
     @InjectRepository(PricingRule) private ruleRepo: Repository<PricingRule>,
     @InjectRepository(Wallet) private walletRepo: Repository<Wallet>,
     @InjectRepository(WalletTransaction) private txRepo: Repository<WalletTransaction>,
+    @InjectRepository(PlatformSetting) private settingsRepo: Repository<PlatformSetting>,
   ) {}
 
   // ─── Service Plans ────────────────────────────────────────────────
@@ -143,6 +145,7 @@ export class BillingService {
     const hasRedis = dto.enableRedis || false;
     const hasRabbitmq = dto.enableRabbitmq || false;
     const hasElasticsearch = dto.enableElasticsearch || false;
+    const hasCustomDomain = dto.enableCustomDomain || false;
 
     const breakdown: { label: string; hourly: number; monthly: number; yearly: number }[] = [];
     let totalBase = 0;
@@ -184,6 +187,10 @@ export class BillingService {
           cost = hasElasticsearch ? Number(rule.unitPrice) : 0;
           label = 'Elasticsearch addon';
           break;
+        case PricingResourceType.CUSTOM_DOMAIN_ADDON:
+          cost = hasCustomDomain ? Number(rule.unitPrice) : 0;
+          label = 'Custom domain + SSL';
+          break;
       }
 
       if (cost > 0) {
@@ -222,6 +229,33 @@ export class BillingService {
     return parseFloat(memory) / (1024 * 1024 * 1024);
   }
 
+  // ─── Custom Domain Pricing (PlatformSetting) ────────────────────
+
+  async getCustomDomainPrice(): Promise<{ monthlyPrice: number }> {
+    const setting = await this.settingsRepo.findOne({
+      where: { key: 'custom_domain_monthly_price_toman' },
+    });
+    return { monthlyPrice: setting ? Number(setting.value) : 0 };
+  }
+
+  async setCustomDomainPrice(monthlyPrice: number): Promise<{ monthlyPrice: number }> {
+    let setting = await this.settingsRepo.findOne({
+      where: { key: 'custom_domain_monthly_price_toman' },
+    });
+    if (setting) {
+      setting.value = String(monthlyPrice);
+    } else {
+      setting = this.settingsRepo.create({
+        key: 'custom_domain_monthly_price_toman',
+        value: String(monthlyPrice),
+        description: 'Monthly price for custom domain addon (Toman)',
+      });
+    }
+    await this.settingsRepo.save(setting);
+    this.logger.log(`Custom domain monthly price updated: ${monthlyPrice} Toman`);
+    return { monthlyPrice };
+  }
+
   // ─── Wallet ───────────────────────────────────────────────────────
 
   async getOrCreateWallet(userId: string): Promise<Wallet> {