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/scenario/scenario.entity.ts

@@ -7,6 +7,7 @@ import {
   OneToMany,
 } from "typeorm";
 import { ScenarioStepEntity } from "./scenario-step.entity";
+import { ScenarioCredentialEntity } from "./scenario-credential.entity";
 
 @Entity("scenarios")
 export class ScenarioEntity {
@@ -22,6 +23,12 @@ export class ScenarioEntity {
   })
   steps: ScenarioStepEntity[];
 
+  @OneToMany(() => ScenarioCredentialEntity, (sc) => sc.scenario, {
+    cascade: true,
+    eager: false,
+  })
+  scenarioCredentials: ScenarioCredentialEntity[];
+
   @CreateDateColumn()
   createdAt: Date;