Casmo/tower-defense — reverse-engineered prompt

Build me a simple 3D tower defense game that runs right in the browser from a single HTML entry point, using plain JavaScript and Three.js. I want something I can open locally in Chrome or Firefox and just play.

The game should have a basic map or path, enemies that move along it, towers I can place, towers that shoot at enemies, health or score, and a simple game UI so it feels playable instead of just being a graphics demo. Use simple placeholder 3D models or basic shapes if needed, but keep the scene clearly readable.

If you can, include a few nice extras that fit a tower defense game, like waves of enemies, different tower shot types, upgrades, multiple levels, and saving score or progress. Keep it lightweight and easy to run, no complicated setup if possible.

Please wire everything up so the project feels complete and polished enough to demo. If you need details on current Three.js patterns, look up the latest docs online.