Point-and-click deletion of fillets and chamfers

Pressing Delete on a Chamfer selection is not working as of now. Probably need to handle more cases in https://github.com/KittyCAD/modeling-app/blob/59103a2118d8ea4b005f96fdfb5a606975cfa7ad/src/lang/modifyAst.ts#L1165

<img width="1512" alt="Image" src="https://github.com/user-attachments/assets/adca0da0-1f72-417e-9e7d-82d5beae312e" />