CRUX M8: Deployment — 11 missing stories

[noahgift]

Parent: #917

Scope

Kubernetes / Docker / systemd / Nix / brew packaging + release channels.

Contracts in scope

• contracts/crux-K-{05,12,13,14,15,16,17,18,19,20,21}-v1.yaml

Exit criteria

• 11 contracts promoted missing → supported
• Reproducible builds + signed release pipeline + package manifests

Dependencies

• Blocks on: v0.31.2 release pipeline stability (currently achieved)
• Blocked by: none CRUX-side