feat(billing): cap each owner's stored file volume

Co-authored-by: Cursor <cursoragent@cursor.com>

apps/api/src/platform/dto.ts

@@ -4,8 +4,10 @@ import {
   IsEmail,
   IsIn,
   IsInt,
+  IsNumber,
   IsOptional,
   IsString,
+  Max,
   MaxLength,
   Min,
   MinLength,
@@ -146,6 +148,15 @@ export class ApplyBillingPlanDto {
   status?: 'active' | 'expired' | 'suspended';
 }
 
+export class SetStorageQuotaDto {
+  /** گیگابایت؛ null = بدون سقف */
+  @IsNumber()
+  @Min(0)
+  @Max(100_000)
+  @ValidateIf((_, value) => value !== null)
+  quotaGb!: number | null;
+}
+
 export class UpdateOrgModulesDto {
   @IsArray()
   @IsString({ each: true })