feat(scenarios): add step title, scenario credentials, and environment context in executor

- add nullable title column to scenario steps; exposed in create/edit forms and step table
- add scenario-credential join (many-to-many with CredentialEntity) with CRUD endpoints
- expose environment URLs in code executor helpers via helpers.env and helpers.getEnvUrl()
- resolve and cache environment per run from the login step's environmentName in scheduler
- add section spacing and step table title column to ScenarioDetailPage

server/src/credential/credential.service.ts

@@ -0,0 +1,56 @@
+import { Injectable, NotFoundException } from "@nestjs/common";
+import { InjectRepository } from "@nestjs/typeorm";
+import { Repository } from "typeorm";
+import { CredentialEntity } from "./credential.entity";
+import { CreateCredentialDto } from "./dto/create-credential.dto";
+import { UpdateCredentialDto } from "./dto/update-credential.dto";
+import {
+  PaginationQueryDto,
+  PaginatedResult,
+} from "../common/dto/pagination.dto";
+
+export type CredentialOrderBy = "id" | "name" | "lastUsedAt" | "createdAt" | "updatedAt";
+
+@Injectable()
+export class CredentialService {
+  constructor(
+    @InjectRepository(CredentialEntity)
+    private readonly repo: Repository<CredentialEntity>,
+  ) {}
+
+  async create(dto: CreateCredentialDto): Promise<CredentialEntity> {
+    return this.repo.save(this.repo.create({ ...dto, data: dto.data ?? null }));
+  }
+
+  async findAll(
+    query: PaginationQueryDto<CredentialOrderBy> = {},
+  ): Promise<PaginatedResult<CredentialEntity>> {
+    const page = query.page ?? 1;
+    const limit = query.limit ?? 20;
+    const orderBy = query.orderBy ?? "id";
+    const orderDir = query.orderDir ?? "ASC";
+    const [data, total] = await this.repo.findAndCount({
+      order: { [orderBy]: orderDir },
+      skip: (page - 1) * limit,
+      take: limit,
+    });
+    return { data, total, page, limit };
+  }
+
+  async findOne(id: number): Promise<CredentialEntity> {
+    const credential = await this.repo.findOneBy({ id });
+    if (!credential) throw new NotFoundException(`Credential ${id} not found`);
+    return credential;
+  }
+
+  async update(id: number, dto: UpdateCredentialDto): Promise<CredentialEntity> {
+    const credential = await this.findOne(id);
+    Object.assign(credential, dto);
+    return this.repo.save(credential);
+  }
+
+  async remove(id: number): Promise<void> {
+    await this.findOne(id);
+    await this.repo.delete(id);
+  }
+}