Implements issue #14. A dedicated thread owns SDL3 (3.4.16, statically
linked via sdl3 =0.20.0) and publishes per-slot snapshots re-expressed as
the XInput-shaped XboxState, so the TU3 conversion in skate-core is
unchanged. Conversions are exact for XInput-backed pads (stick Y via
bitwise NOT, trigger round-to-nearest). SKATE3_INPUT=xinput selects the
original transport, which is also the fallback if SDL fails to start.
Optional settings/controller.json maps paddles to XInput buttons.
Build: scripts/Ensure-CMake.ps1 locates CMake (PATH or Visual Studio's
copy) for the SDL source build. sdl3-sys is vendored with a build.rs
patch setting CMAKE_MSVC_RUNTIME_LIBRARY from crt-static, because SDL's
CMake (policy CMP0091) ignores cmake-rs' -MT and the static-CRT release
build failed with unresolved __imp_* symbols.
See docs/hails-additions/03-sdl3-gamepad-input.md and vendor/README.md.
Add generalized engine access and challenge mods, repair SKATE turn handling, and improve collision prediction and physics transitions. Reduce mod snapshot and material update overhead, preserve authored GLB materials with lighting and shadows, and improve CPU profiling.
Hails