refactor(workspace): restore yaml exports and align docker builds

- return scenario export payloads as yaml to match existing workflows

- harden step reordering flow for drag-and-drop and one-based ui labels

- switch server container to workspace-lockfile installs and root ignore rules

server/src/scenario/dto/create-scenario-step.dto.ts

@@ -1,5 +1,5 @@
-import { ApiProperty, ApiPropertyOptional } from "@nestjs/swagger";
-import { IsInt, IsNotEmpty, IsOptional, IsString, Min } from "class-validator";
+import { ApiPropertyOptional } from "@nestjs/swagger";
+import { IsNotEmpty, IsOptional, IsString } from "class-validator";
 
 export class CreateScenarioStepDto {
   @ApiPropertyOptional({ example: "Check login page title" })
@@ -7,11 +7,6 @@ export class CreateScenarioStepDto {
   @IsString()
   title?: string;
 
-  @ApiProperty({ example: 0, description: "Execution order (ascending)" })
-  @IsInt()
-  @Min(0)
-  order: number;
-
   @ApiPropertyOptional({
     description:
       "Session name (deprecated — browser is created automatically per run).",