feat(scenario): add scheduler, cancelled step status, and runs list endpoint

- install @nestjs/schedule and register ScheduleModule in AppModule
- add ScenarioSchedulerService with two 1s interval jobs:
  - activatePendingRuns: flips pending runs to in_progress
  - processPendingStepRuns: executes next pending step run (login or exec),
    runs optional validateCode, advances or fails the run accordingly
- on step pass: next waiting step becomes pending; last step pass flips run to pass
- on step fail: remaining steps set to cancelled, run flipped to fail
- add cancelled to RunStepStatus union
- add GET /scenarios/:id/runs with pagination and optional ?status= filter

src/scenario/scenario.controller.ts

@@ -17,6 +17,7 @@ import { UpdateScenarioDto } from './dto/update-scenario.dto';
 import { CreateScenarioStepDto } from './dto/create-scenario-step.dto';
 import { UpdateScenarioStepDto } from './dto/update-scenario-step.dto';
 import { PaginationQueryDto } from './dto/pagination-query.dto';
+import { RunsQueryDto } from './dto/runs-query.dto';
 
 @ApiTags('scenarios')
 @Controller('scenarios')
@@ -114,6 +115,17 @@ export class ScenarioController {
 
   // ── Runs ──────────────────────────────────────────────────────────────────
 
+  @Get(':id/runs')
+  @ApiOperation({ summary: 'List runs for a scenario (paginated, filterable by status)' })
+  @ApiResponse({ status: 200 })
+  @ApiResponse({ status: 404, description: 'Scenario not found' })
+  findRuns(
+    @Param('id', ParseIntPipe) id: number,
+    @Query() query: RunsQueryDto,
+  ) {
+    return this.scenarioService.findRuns(id, query);
+  }
+
   @Post(':id/run')
   @ApiOperation({ summary: 'Create a new run for a scenario' })
   @ApiResponse({ status: 201, description: 'Run created with step runs' })