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## Summary

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## Test plan

<!-- Bullet list of what you actually ran. Be specific.
     - `make test` → green
     - Manually exercised the new flow at /hosts/{id}/foo
     - Smoke env: enrolled a fresh host, ran a backup end-to-end
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## Notes for the reviewer

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     diff: related issue, follow-up work that's intentionally not
     in this PR, deferred concerns, design alternatives considered
     and rejected. -->

## Linked issues

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