make sshsigchain the only portable sigchain format

docs/adr/0018-sshsigchain.md

@@ -1,9 +1,10 @@
-# ADR 0018: Linked SSHSIGCHAIN v2
+# ADR 0018: Linked SSHSIGCHAIN v1
 
 ## Status
 
-Accepted for the new generic core and geth keychain profile. Legacy static
-sigchain publication is deprecated pending explicit v2 command migration.
+Accepted for the generic core and geth keychain profile. The pre-standard
+test-only static workflow is removed; it is not an alternate format or a
+compatibility path.
 
 ## Context
 
@@ -14,7 +15,7 @@ rollback, and fork semantics inadequate for a trust foundation.
 
 ## Decision
 
-Geth adopts SSHSIGCHAIN v2 as the replacement design:
+Geth adopts SSHSIGCHAIN version 1 as its one portable signed-chain design:
 
 - root trust is an explicit `(chain ID, profile, namespace, root key)` tuple;
 - records are linearly ordered by sequence and linked by a digest over their
@@ -31,11 +32,11 @@ not a geth transport.
 
 ## Consequences
 
-The v2 core can be published and implemented by applications without importing
+The core can be published and implemented by applications without importing
 geth's resource model. Geth's keychain profile is intentionally narrow and
 tested against self-bootstrap, fork, and backdated-revocation attacks.
 
-Existing static v1 bundles cannot safely migrate in place. Operators must pin a
-new v2 trust tuple and create a new genesis chain. Head persistence and later
-witness/transparency support remain follow-up work; neither is implied by a
-single signed checkpoint.
+The old static bundle code and commands are deleted rather than supported beside
+SSHSIGCHAIN. There is no migration format because the repository has not been
+deployed. Head persistence and later witness/transparency support remain
+follow-up work; neither is implied by a single signed checkpoint.