feat: import and export tickets as CSV

Every ticket of a project can be downloaded as CSV, and a CSV exported
from TaskStream or from Jira can be imported: types, statuses, priorities
and people are matched by id or name, the rest falls back with a warning,
and parents are rebuilt. The settings page previews an import before it
creates anything.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/api/tracker/presenters/src/lib/http/dto/requests.dto.ts

@@ -754,6 +754,17 @@ export class UpdateWebhookDto extends PartialType(CreateWebhookDto) {
   active?: boolean;
 }
 
+export class ImportQueryDto {
+  @ApiPropertyOptional({
+    default: false,
+    description: 'Only tell what would be created',
+  })
+  @IsOptional()
+  @Transform(toBoolean)
+  @IsBoolean()
+  dryRun = false;
+}
+
 export class RankIssueDto {
   @ApiPropertyOptional({
     type: String,