refactor: centralize core api helpers

scripts/smoke-core-package.ts

@@ -0,0 +1,7 @@
+import assert from "node:assert/strict";
+
+const coreModule = await import("comfyui-node-organizer/core");
+
+assert.equal(typeof coreModule.inferGroupMembership, "function");
+assert.equal(typeof coreModule.normalizeWorkflowGeometry, "function");
+assert.equal(typeof coreModule.DEFAULT_FRAMEWORK_CONFIG, "object");