-- Drop the asymmetric commit signature from space repo state.
--
-- Permissioned Data Diary 7 establishes that asymmetric signatures on data are
-- an anti-pattern for permissioned data: a signature is an irrevocable,
-- redistributable proof of authenticity that survives escaping the space's
-- access boundary. Space commits are now authenticated solely by the deniable
-- HMAC (`mac`, keyed from the per-commit `ikm`).
--
-- The column was never populated in production — the commit machinery had no
-- production callers until the write path was wired up alongside this change.
ALTER TABLE happyview_space_repo_state DROP COLUMN sig;