qev web-engine corresponding source

The modified C/header sources actually used by the web build are in upstream/WinQuake.
The integration sources, patch, input manifest and reproduction scripts are in qev/.
SDL 2.30.9 source and license are included. No proprietary game data is included.

Upstream Qwasm: https://github.com/GMH-Code/Qwasm/tree/f56b5e71e4be8effede29bae1785a5306dcc0249
Toolchain: Emscripten 3.1.74, installed by the pinned setup-toolchain.sh.
Integration SHA-256: 1ff67141976d62dda11809ec39a6dea94980a6077156f31f18ddc5554816420f

To reproduce with Node.js 22+, Git, Python 3 and make:
  cd qev
  bash scripts/setup-toolchain.sh
  node scripts/build-engine.mjs
These scripts fetch the pinned upstream/toolchain and apply the supplied patch/modules.
The already-modified upstream sources and generated Makefile.qev are also provided for inspection and offline rebuilding with that toolchain.

Public project and build instructions: https://github.com/robtandy/qev
The engine/integration is GPL-2.0-or-later; see upstream/COPYING and qev/engine/COPYING.
SDL is zlib-licensed; see SDL2-2.30.9/LICENSE.txt. Emscripten uses MIT/UIUC licenses; see EMSCRIPTEN-LICENSE.txt.
