feat(deploy): configurable CPU/RAM/disk for app databases

Let users size the database workload from the deploy wizard the same way
Redis/RabbitMQ are configured: a resource card (CPU request/limit, memory
request/limit, storage) on the Resources step, stored in
optionalServiceResources.database.

- entity/DTO: add `database` to optionalServiceResources
- k8s: resolveDatabaseResources() applies user-selected resources on both
  the Helm and K8s-API deploy paths (was hardcoded 100m/256Mi→500m/512Mi)
- billing: bill database CPU/RAM as a separate line on top of the app's
  resources; merge it through the upgrade path too
- wizard: db resource card on the Resources step, disk moved into the card,
  cost preview + review summary include the database resources

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

backend/src/billing/pricing-catalog.service.ts

@@ -654,8 +654,14 @@ export class PricingCatalogService implements OnModuleInit {
     }
     const replicas = dto.replicas ?? 1;
     const hasDatabase = dto.databaseType !== DatabaseType.NONE && dto.databaseType !== 'none';
-    const cpuQty = this.parseCpuToCores(dto.cpuLimit) * replicas;
-    const memoryQty = this.parseMemoryToGb(dto.memoryLimit) * replicas;
+    let cpuQty = this.parseCpuToCores(dto.cpuLimit) * replicas;
+    let memoryQty = this.parseMemoryToGb(dto.memoryLimit) * replicas;
+    // The database runs as its own single-replica workload; bill its CPU/RAM on
+    // top of the app's, using the user-selected per-database resources.
+    if (hasDatabase && dto.databaseResources) {
+      cpuQty += this.parseCpuToCores(dto.databaseResources.cpuLimit);
+      memoryQty += this.parseMemoryToGb(dto.databaseResources.memoryLimit);
+    }
     const storageQty =
       (dto.dbStorageSize
         ? parseFloat(String(dto.dbStorageSize).replace(/Gi$/i, '')) || 0