Replace the boot-fragile busybox-crond-in-tmux (phase 5 §4) with a
systemd service+timer. Service is timer-triggered only (not wantedBy
multi-user.target) so it never runs on boot/activation; mirrors the
cc-ci-loops env fix (CLAUDE_BIN + /home/loops/.local/bin on PATH).
Timer fires Sundays 02:00 UTC, Persistent=true so a missed run (box
down) fires once on next boot. Runs launch-upgrader.py start ->
cc-ci-upgrader agent -> /upgrade-all DEFAULT (opens recipe PRs, never
merges). Activate via nixos-rebuild + retire the old Monday crond after
the phase-5 T0-fire verification completes.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
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