收口创作入口契约后台表单

将统一创作契约泥点消耗改为数字字段并由前端格式化展示
将后台契约编辑从 JSON 文本改为结构化卡片与弹窗表单
隐藏玩法阶段等内部标识并按玩法默认映射自动带出
更新创作入口文档、团队记忆和回归测试

src/services/creationEntryConfigService.ts

@@ -1,6 +1,8 @@
 import type { PlatformCreationTypeId } from '../../packages/shared/src/contracts/playTypes';
 import { requestJson } from './apiClient';
 
+export const DEFAULT_UNIFIED_CREATION_MUD_POINT_COST = 10;
+
 /** 后端下发的单个创作类型入口配置，前端只据此展示和分流。 */
 export type CreationEntryTypeConfig = {
   id: PlatformCreationTypeId;
@@ -30,6 +32,7 @@ export type UnifiedCreationField = {
 export type UnifiedCreationSpec = {
   playId: PlatformCreationTypeId;
   title: string;
+  mudPointCost?: number | null;
   workspaceStage: string;
   generationStage: string;
   resultStage: string;