Optimization for Up/Down Keyboard Shortcuts

Currently, the fold/expand operation only works on the node where the cursor is located, which is not very user-friendly. We hope to implement traversal folding/expanding of nodes.

Specifically:

• When using Option + ↑, if the current cursor node has a parent node, it should continue folding upward through the parent nodes

• Similarly, when using Option + ↓, it should be able to expand child nodes

In other words, this would enable recursive folding/expanding functionality instead of just operating on the single node where the cursor is positioned.