To bake a normal map in Blender:
 * Create low-poly mesh.
 * Duplicate mesh, add detail.
 * Add a material to low-poly mesh.
 * In shader editor, add an Image Texture.
 * In render settings, set render engine to Cycles, device to GPU Compute.
  * Under Bake, set margin to 0px, bake type to Normal, check "Selected to
    Active" and make sure the Ray Distance is set to something like .1 or 5 or
    whatever, just not 0.
 * In UV Editor, select the image texture.
 * Make high-poly mesh.
 * Select high-poly mesh, then low-poly mesh. Hit Bake.
 * If you want to bake an albedo map, then make your colors emissive and set the
   bake type to Emit instead.
 * Create a new standard-shader material in Unity.
 * Export the baked image(s), and use them as normal/albedo maps on the new
   material.
 * In Blender, make a new material for the lowpoly mesh, named after the new
   material (so that my material reassigner can recognize it).
 * Manually export the lowpoly mesh and collider to Unity using the "ship
   export" settings.