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/test/integration/shared/db/workflows.ts

@@ -25,10 +25,11 @@ export async function createManyWorkflows(
 }
 
 export function newWorkflow(attributes: Partial<IWorkflowDb> = {}): IWorkflowDb {
-	const { active, name, nodes, connections, versionId, settings } = attributes;
+	const { active, isArchived, name, nodes, connections, versionId, settings } = attributes;
 
 	const workflowEntity = Container.get(WorkflowRepository).create({
 		active: active ?? false,
+		isArchived: isArchived ?? false,
 		name: name ?? 'test workflow',
 		nodes: nodes ?? [
 			{