Add edit, save, and cancel buttons to node modal

[charliestoner1]

Changes Made

• Added Edit button to node modal
• Added Save button to save edited values
• Added Cancel button to discard changes
• Edit mode allows editing of all primitive node values
• Values update correctly when saved

Files Modified

• src/features/modals/NodeModal/index.tsx

Testing

• Tested with various JSON data
• Edit button appears in node modal
• Save and Cancel buttons work as expected
• Values can be edited and saved successfully