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/execution-lifecycle/__tests__/execution-lifecycle-hooks.test.ts

@@ -61,6 +61,7 @@ describe('Execution Lifecycle Hooks', () => {
 		id: workflowId,
 		name: 'Test Workflow',
 		active: true,
+		isArchived: false,
 		connections: {},
 		nodes: [],
 		settings: {},