fix(release): sign v1.7.122 with the OLD root — the rotation moved the checks a release early

The rotation commit pointed create-release.sh and publish-release-assets.sh
at the NEW root in the same commit that pins it in the binary. But the
release CARRYING the rotation must be signed with the OLD root: every node
is still running the previous binary, which pins the old key. So the
tooling would have rejected the only signature the fleet can accept, and
the signature it demanded would have ended OTA fleet-wide.

Both checks now expect the old DID for this cycle, with the flip to the new
one called out for v1.7.123+. sign-manifest.sh documents the
ARCHY_RELEASE_ROOT_PUBKEY override needed because the signer built from
this tree already pins the new anchor and would fail to verify its own
correct output.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

scripts/publish-release-assets.sh

@@ -29,7 +29,11 @@ fail() { echo "Error: $*" >&2; exit 1; }
 # with the pinned release-root anchor refuse to auto-apply unsigned manifests,
 # and enforcement will tighten to hard-reject — an unsigned publish would
 # strand them. Grep proves presence; ceremony verify proves the crypto.
-EXPECTED_DID="did:key:z6Mkfu5LT8d4DjETtrkATvHh9Dvcbnr7zBCUwfau8Sw7DLWT"
+# ⚠ ROTATION IN FLIGHT (v1.7.122-alpha) — OLD root on purpose; see the same
+# block in create-release.sh. Nodes still run the previous binary and pin the
+# old key, so the manifest this release publishes must carry an old-key
+# signature. Flip both to z6Mkfu5LT…DLWT for v1.7.123+.
+EXPECTED_DID="did:key:z6MkkidEnEpo6qHMCNSZoNKWtvQvxq3whnaME9wGgEFhq7ur"
 grep -q '"signature":' "$PROJECT_ROOT/releases/manifest.json" \
     && grep -q "\"signed_by\": \"$EXPECTED_DID\"" "$PROJECT_ROOT/releases/manifest.json" \
     || fail "releases/manifest.json is not signed by the release root — run: bash scripts/sign-manifest.sh"