Scripting is now a standard part of the engine rather than an optional
feature: removes the DUSK_SCRIPT CMake option and its compile definition,
makes src/dusk/CMakeLists.txt add_subdirectory(script) unconditionally, and
drops the #ifdef DUSK_SCRIPT guards around scriptInit()/scriptDispose() in
engine.c. duskscriptcc and its test still only build on the linux/knulli
host target (it's a dev tool, not part of the runtime), now gated on that
alone instead of DUSK_SCRIPT AND that.
Co-Authored-By: Claude Sonnet 5 <[email protected]>