revert(build): remove app build pipeline revamp (Nixpacks/MinIO/Trivy/registry GC)

Reverts commits 3eff38f and c379a23 and restores the previous Kaniko-only
build pipeline (runtime detection + per-runtime Dockerfile generation,
disk-based source upload).

Removed: Nixpacks Dockerfile generation, MinIO source storage (common/storage),
Bull build queue + Redis build state (common/redis, deployment.processor),
Trivy image scan (scan.service, deployment.vulnerabilitySummary), and daily
registry garbage collection (registry-gc). Nothing outside the build/deploy
path depended on these. Backend tsc + 105/106 tests green (the pre-existing
helm.service chartPath failure is unrelated); frontend tsc green.

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

backend/src/kubernetes/kubernetes.module.ts

@@ -3,7 +3,6 @@ import { TypeOrmModule } from '@nestjs/typeorm';
 import { KubernetesService } from './kubernetes.service';
 import { HelmService } from './helm.service';
 import { RegistryService } from './registry.service';
-import { RegistryGcService } from './registry-gc.service';
 import { ElasticsearchService } from './elasticsearch.service';
 import { ElasticsearchController } from './elasticsearch.controller';
 import { LogsController } from './logs.controller';
@@ -14,7 +13,7 @@ import { Deployment } from '../deployments/entities/deployment.entity';
 @Module({
   imports: [forwardRef(() => ClustersModule), TypeOrmModule.forFeature([Application, Deployment])],
   controllers: [ElasticsearchController, LogsController],
-  providers: [KubernetesService, HelmService, RegistryService, RegistryGcService, ElasticsearchService],
+  providers: [KubernetesService, HelmService, RegistryService, ElasticsearchService],
   exports: [KubernetesService, HelmService, RegistryService, ElasticsearchService],
 })
 export class KubernetesModule {}