feat(f4): add append-only INF follow-up DTO

api-v3/src/inspection-reports/dto/create-inspection-report-follow-up.dto.ts

@@ -0,0 +1,23 @@
+import { Transform } from 'class-transformer';
+import { IsEnum, IsISO8601, IsOptional, IsString, MaxLength } from 'class-validator';
+import { InspectionReportFollowUpType } from '../../database/entities';
+
+export class CreateInspectionReportFollowUpDto {
+  @IsEnum(InspectionReportFollowUpType)
+  type!: InspectionReportFollowUpType;
+
+  @IsISO8601({ strict: true })
+  occurredAt!: string;
+
+  @IsOptional()
+  @Transform(({ value }) => typeof value === 'string' ? value.trim() || null : value)
+  @IsString()
+  @MaxLength(255)
+  externalReference?: string | null;
+
+  @IsOptional()
+  @Transform(({ value }) => typeof value === 'string' ? value.trim() || null : value)
+  @IsString()
+  @MaxLength(20000)
+  description?: string | null;
+}