feat(core): Change workflow deletions to soft deletes (#14894)

Adds soft‑deletion support for workflows through a new boolean column `isArchived`.

When a workflow is archived we now set `isArchived` flag to true and the workflows
stays in the database and is omitted from the default workflow listing query.

Archived workflows can be viewed in read-only mode, but they cannot be activated.

Archived workflows are still available by ID and can be invoked as sub-executions,
so existing Execute Workflow nodes continue to work. Execution engine doesn't
care about isArchived flag.

Users can restore workflows via Unarchive action at the UI.

packages/cli/src/environments.ee/source-control/source-control-export.service.ee.ts

@@ -106,6 +106,7 @@ export class SourceControlExportService {
 					versionId: e.versionId,
 					owner: owners[e.id],
 					parentFolderId: e.parentFolder?.id ?? null,
+					isArchived: e.isArchived,
 				};
 				this.logger.debug(`Writing workflow ${e.id} to ${fileName}`);
 				return await fsWriteFile(fileName, JSON.stringify(sanitizedWorkflow, null, 2));