XProger/OpenLara — reverse-engineered prompt

Build me an open source engine for the classic Tomb Raider games that can run as a standalone app and also in the browser as a WebGL demo. I want it to load and play a demo level, render the old school 3D environments with nice lighting and water effects like the screenshots, and feel like the original games rather than a remake.

Keep the focus on the core engine, basic menus, input, camera, movement, combat, cutscenes, and support for original game content where possible. Make it easy to launch locally and include a simple playable demo so I can verify it works right away. If there are gaps, use the roadmap and public docs online to fill them in, but stay faithful to the classic Tomb Raider experience.