Try the Stackblitz
Use npm install and then npm run start.
See:
threejs - the web 3d framework
three-pathfinding - pathfinding via navmesh in threejs
UPBGE - used for building level mesh and the navmesh
Blender project is inside blender folder and can be opened with UPBGE. GLB files (level and navmesh) are contained in dist/glb.