Currently, Unity does not provide a built-in solution for Lightmapping at runtime within a standalone build. This constraint impacts the development of your level editor and similar tools that require efficient pre-computed lighting for dynamically generated scenes, as real-time lighting often impacts performance. To manage lighting in your level editor, follow these architectural steps:

1. Verify that the Lightmapping engine is not invoked in runtime scripts to avoid compilation errors during the build phase.
2. Implement Adaptive Probe Volumes (APV) to provide high-quality global illumination that can be adjusted more flexibly than traditional Lightmapping.
3. Use ReflectionProbe.RenderProbe to dynamically update specular reflections when your level editor environment is modified by the user.
4. Utilize the GPU Resident Drawer in Unity 6 to optimize the performance of real-time lights, which can serve as a substitute for baked Lightmapping data.
5. Explore third-party runtime baking plugins that utilize custom compute shaders to bypass the native UnityEditor restrictions.

Additional Tips:

• Use LightmapSettings to dynamically swap existing baked textures if your level editor utilizes a modular system with pre-defined assets.
• Monitor the development of the modular Lightmapping backend, which is intended to decouple baking processes from the Editor in future Unity 6 iterations.