tidy up old code

frontend/src/canvasInteractionTargets.ts

@@ -1,50 +0,0 @@
-const EXCLUDED_CANVAS_TARGETS = '.context-menu, .react-flow__node, .react-flow__edge, .react-flow__controls, .react-flow__minimap, .surface-view-container';
-const CANVAS_AREA_TARGETS = '.react-flow, .react-flow__renderer, .react-flow__viewport, .react-flow__pane, .react-flow__background, .react-flow__selectionpane';
-
-function getTargetElement(target: EventTarget | null): Element | null {
-  if (!target) return null;
-  if (typeof (target as Element).closest === 'function') return target as Element;
-  const parent = (target as Node).parentElement;
-  if (parent && typeof parent.closest === 'function') {
-    return parent;
-  }
-  return null;
-}
-
-function supportsClosest(target: EventTarget | null): boolean {
-  return !!getTargetElement(target);
-}
-
-function matchesClosest(target: EventTarget | null, selector: string): boolean {
-  const element = getTargetElement(target);
-  return !!element && element.closest(selector) !== null;
-}
-
-export function isEditableInteractionTarget(target: EventTarget | null): boolean {
-  if (!supportsClosest(target)) return false;
-  if (matchesClosest(target, 'input, textarea, select')) return true;
-  return matchesClosest(target, '[contenteditable="true"]');
-}
-
-export function canStartCanvasRightDragZoomTarget(target: EventTarget | null): boolean {
-  if (!supportsClosest(target)) return false;
-  if (isEditableInteractionTarget(target)) return false;
-  if (matchesClosest(target, EXCLUDED_CANVAS_TARGETS)) {
-    return false;
-  }
-  return matchesClosest(target, CANVAS_AREA_TARGETS);
-}
-
-export function canOpenCanvasContextMenuTarget(target: EventTarget | null): boolean {
-  if (!supportsClosest(target)) return false;
-  if (isEditableInteractionTarget(target)) return false;
-  if (matchesClosest(target, EXCLUDED_CANVAS_TARGETS)) {
-    return false;
-  }
-  return matchesClosest(target, CANVAS_AREA_TARGETS);
-}
-
-export function isSecondaryCanvasContextEvent(event: MouseEvent | null): boolean {
-  if (!event || typeof event.button !== 'number') return false;
-  return event.button === 2 || (event.button === 0 && !!event.ctrlKey);
-}