[squad:plan] Lattice Hollow — M4 Playable Demo: "Open Circuit" (McManus)

[github-actions]

Owner: McManus — Build/Release

Part of the Lattice Hollow plan (#58481).

Goals:

• Package a stable external-facing demo build for internal sharing or event testing.
• Deliverables: build pipeline, versioning approach, downloadable artifact, basic crash/reporting checklist.
• Platform specifics for PC distribution, controller/keyboard validation.
• Release gates tied to performance, save integrity, and known-issues triage.

Depends on #58477 and #58478 completion.