Run clang-format (the repo's .clang-format: LLVM base, 120 cols, tabs,
Allman functions) over every source file so the tree is formatter-clean.
Whitespace only -- no behavior change; full x64 + x86 suites pass.
Also set SortIncludes: false in .clang-format. Windows include order is
load-bearing (windows.h must precede tlhelp32.h / mmreg.h / xinput.h /
dinput.h; winsock2.h must precede windows.h), and the default
alphabetical sort reorders tlhelp32.h ahead of windows.h -- a build
break. Leaving order alone keeps the manual, correct grouping.
Add SteamInputSource: initializes SteamAPI + Steam Input, loads a bundled action
manifest via SetInputActionManifestFilePath (no partner-backend config needed),
and reads the GameControls action set into CoopPadState -- falling back to XInput
per slot, and to pure XInput if Steam isn't available, so the host always runs.
Enabled automatically when the Steamworks SDK is vendored at
third_party/steamworks_sdk/ (auto-detected by CMake; gitignored and never
committed -- the build is XInput-only without it). Stages steam_api64.dll + the
manifest next to the host and builds coop_steam_input_probe (a console smoke test).
Verified: the probe initializes against the live Steam client and enumerates
controllers; the host degrades gracefully when launched standalone. All 5 tests
pass. Reading actual controller state needs a pad bound through Steam Input for
the running (donor) appid, which XInput otherwise covers.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
