feat(browser,mcp): resolve environment and credentials from DB in exec

- POST /exec now accepts environmentId (UUID) and credentials (alias → UUID)
  instead of raw payloads; resolves entities via EnvironmentService and
  CredentialService before passing data to browserService.exec
- exec_code MCP tool updated with same schema: environmentId + credentials map
- CredentialModule imported into BrowserModule and McpModule
- docs(scenario): rewrite script runtime section for single context argument
- docs(mcp): update exec_code description to reflect new parameter shapes
- style: reorder imports across server source (formatter)

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

@@ -12,5 +12,4 @@ export class CreateScenarioStepDto {
   @IsString()
   @IsNotEmpty()
   execCode?: string;
-
 }

server/src/scenario/dto/scenario-export.dto.ts

@@ -22,7 +22,6 @@ export class ScenarioStepExportDto {
   @IsString()
   @IsNotEmpty()
   execCode: string | null;
-
 }
 
 export class ScenarioExportDto {

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

@@ -18,5 +18,4 @@ export class UpdateScenarioStepDto {
   @IsString()
   @IsNotEmpty()
   execCode?: string;
-
 }

server/src/scenario/dto/update-scenario.dto.ts

@@ -1,5 +1,5 @@
 import { ApiPropertyOptional } from "@nestjs/swagger";
-import { IsOptional, IsString, IsNotEmpty } from "class-validator";
+import { IsNotEmpty, IsOptional, IsString } from "class-validator";
 
 export class UpdateScenarioDto {
   @ApiPropertyOptional({ example: "Updated scenario name" })