Captures the four grey areas team-lead flagged in the sprint 0 brief
(regex_extract semantics, output_blob_ref storage, /hosts/sync merge
behaviour, payload_type↔home-C2 mapping) plus stale-host policy.
No decisions taken: each entry lists options, a recommended default
if no decision is reached, and a "becomes blocking when…" trigger.
Resolved questions will move to spec-decisions.md as D-NNN entries.
