refactor(view): extract canvas viewport hooks

view/canvas/cursor.ts

@@ -0,0 +1,8 @@
+import type { InteractionMode } from "@editor/tools";
+import type { CanvasInputState } from "./useCanvasInput";
+
+export function canvasCursorClass(interactionMode: InteractionMode, input: CanvasInputState) {
+  if (input.isPanning) return "cursor-grabbing";
+  if (interactionMode.type === "temporary-pan") return "cursor-grab";
+  return "cursor-default";
+}