feat(base): disable type-conversion API for v1, preserve engine for v2

apps/server/src/core/base/dto/update-property.dto.ts

@@ -1,12 +1,11 @@
 import {
-  IsIn,
+  IsEmpty,
   IsNotEmpty,
   IsObject,
   IsOptional,
   IsString,
   IsUUID,
 } from 'class-validator';
-import { BASE_PROPERTY_TYPES } from '../base.schemas';
 
 export class UpdatePropertyDto {
   @IsUUID()
@@ -20,8 +19,14 @@ export class UpdatePropertyDto {
   @IsNotEmpty()
   name?: string;
 
-  @IsOptional()
-  @IsIn(BASE_PROPERTY_TYPES)
+  /*
+   * Type changes are intentionally not exposed via the API in v1. The
+   * conversion engine in apps/server/src/core/base/engine/ and the
+   * worker in tasks/base-type-conversion.task.ts remain intact for
+   * a future v2 re-wire. Requests including `type` are rejected here
+   * so the service's type-change branches stay unreachable.
+   */
+  @IsEmpty()
   type?: string;
 
   @IsOptional()