fix: properly clean up child nodes when deleting Iteration Box

[octo-patch]

Fixes #13889

Problem

When an Iteration Box container is deleted (via keyboard Delete/Backspace), child nodes inside it are not properly cleaned up. They remain in the underlying data structure and the exported JSON file, which causes workflow editing instability, inability to link/connect nodes, node/edge rendering failures, and browser console exceptions.

There is also a secondary bug in deleteIterationNodeById (toolbar delete button): the edge filter uses && instead of ||, so edges connected to child nodes are never removed.

Solution

Fix 1: use-before-delete.tsx — When keyboard deletion triggers handleBeforeDelete, explicitly collect all child nodes (nodes with parentId matching the deleted Iteration Box ID) and include them in toBeDeletedNodes.

Fix 2: store.ts — deleteIterationNodeById — Fixed the edge filter from && to ||:

// Before (always false — no edge has source === target):
!children.some((child) => edge.source === child.id && edge.target === child.id)
// After:
!children.some((child) => edge.source === child.id || edge.target === child.id)

Testing

1. Create an agent workflow with an Iteration Box containing nodes inside.
2. Select the Iteration Box and press Delete/Backspace — child nodes should also be removed.
3. Export the workflow JSON and verify no orphaned child nodes remain.
4. Use toolbar delete button on Iteration Box — verify no dangling edges remain.

[cike8899]

Which version are you using? I haven't been able to reproduce this problem in the latest code on the main branch. @octo-patch