internal/engine/protection_units.go has no production implementation

[vishr]

The file is 274 lines. ProtectionUnitTarget (:61), ReconcileProtectionUnits (:124), and InspectProtectionUnits (:203) are referenced only from protection_units_test.go, which supplies an in-memory memoryProtectionSystemd double. There is no implementation of the interface outside tests and no caller in cmd/ or internal/.

Live scheduling goes through internal/engine/schedule.go instead, which writes units directly and has its own ownership convention.

Worth resolving one way or the other, since the two files encode different rules for the same host resource: protection_units.go embeds X-Onebox-* ownership metadata and refuses to overwrite foreign units, while schedule.go matches on filename prefix alone.

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Removed in #51 (f9ef6bc). Split out of #50 as item 7.

[vishr]

Removed in #51 (f9ef6bc).

[vishr]

Reopening context rather than the issue: the deletion this tracked was probably wrong.

protection_units.go is a listed deliverable of #22, which enumerates "canonical locks, fencing, journals, credentials, runner envelopes, and systemd units" and states that "database backup and restore engines follow as separate slices". It had no caller because the slices that would install and invoke it were never built, not because it was abandoned.

It also held the stronger of the two systemd ownership models — X-Onebox-* unit metadata plus a refusal to overwrite a foreign-owned unit — against schedule.go, which matches on filename prefix alone. That is the substance of #56 and #57.

Recoverable with git show f9ef6bc^:internal/engine/protection_units.go. Full context and the decision to make in #63.