refactor: defaults should be in their own file, respecting eslint/ react standards. all tests fail, obviously.

ref: N25B-294

src/pages/VisProgPage/visualProgrammingUI/components/DragDropSidebar.tsx

@@ -3,7 +3,6 @@ import { useReactFlow, type XYPosition } from '@xyflow/react';
 import { type ReactNode, useCallback, useRef, useState } from 'react';
 import useFlowStore from '../VisProgStores';
 import styles from '../../VisProg.module.css';
-import type { AppNode } from '../VisProgTypes';
 import { NodeDefaults, type NodeTypes } from '../NodeRegistry'
 
 /**
@@ -48,7 +47,7 @@ function DraggableNode({ className, children, nodeType, onDrop }: DraggableNodeP
  * addNode — adds a new node to the flow using the unified class-based system.
  * Keeps numbering logic for phase/norm nodes.
  */
-export function addNode(nodeType: keyof typeof NodeTypes, position: XYPosition) {
+  function addNode(nodeType: keyof typeof NodeTypes, position: XYPosition) {
   const { nodes, setNodes } = useFlowStore.getState();
   const defaultData = NodeDefaults[nodeType]
 
@@ -67,7 +66,7 @@ export function addNode(nodeType: keyof typeof NodeTypes, position: XYPosition)
 
   const id = `${nodeType}-${nextNumber}`;
   
-  let newNode = {
+  const newNode = {
     id: id,
     type: nodeType,
     position,
@@ -106,7 +105,7 @@ export function DndToolbar() {
 
 
   const droppableNodes = Object.entries(NodeDefaults)
-  .filter(([_, data]) => data.droppable)
+  .filter(([, data]) => data.droppable)
   .map(([type, data]) => ({ 
     type: type as DraggableNodeProps['nodeType'], 
     data