Steam: build and upload pipeline, in step with the web deploy #166

Part of #142 · Milestone 3: Playable desktop build (Windows) · plan item 3.8

Size: M · Owner-only step: no

What

GitHub Actions builds the Windows and Linux apps and uploads both depots with Steam's tools. Steam must get every update no later than any other place the game is released, so the web deploy and the Steam upload go together.

Decision / recommendation

One workflow: Pages deploy and Steam upload (to a beta branch) from the same commit; the owner sets builds live.

Done when

• Every merge to main reaches the Steam beta branch

Sources

• https://partner.steamgames.com/doc/sdk/uploading

Plan page (owner only): https://claude.ai/artifact/Cf5SWQHzAKTy2uHCC1UQgw