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

**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.

Read the parent plan #58481 and prerequisites #58477 and #58478 first; this issue names no implementation files or tests. Define the build and release entry points, then verify completion against the downloadable PC artifact, versioning approach, crash/reporting checklist, input validation, and performance, save-integrity, and known-issues gates.

Written by the indexing model from the issue text.