remove the old snapshot store; tombstone its options

nix/host-modules/deploy.nix

@@ -68,6 +68,12 @@ let
     there is no agent-base closure to pre-fetch into the host store. Remove
     this definition.
   '';
+
+  # Shared by the removed options of the snapshot store.
+  snapshotStoreRemoved = ''
+    The snapshot store was removed; agent-state backups are being rebuilt as
+    swarm-archive. Remove this definition.
+  '';
 in
 {
   imports = [
@@ -143,6 +149,38 @@ in
       "queue"
       "agentCredentialDir"
     ] queueAgentCredentialRemoved)
+    (lib.mkRemovedOptionModule [
+      "services"
+      "hyperhive"
+      "swarm"
+      "snapshotStore"
+      "address"
+    ] snapshotStoreRemoved)
+    (lib.mkRemovedOptionModule [
+      "services"
+      "hyperhive"
+      "swarm"
+      "snapshotStore"
+      "port"
+    ] snapshotStoreRemoved)
+    (lib.mkRemovedOptionModule [
+      "services"
+      "hyperhive"
+      "snapshotStore"
+      "enable"
+    ] snapshotStoreRemoved)
+    (lib.mkRemovedOptionModule [
+      "services"
+      "hyperhive"
+      "snapshotStore"
+      "path"
+    ] snapshotStoreRemoved)
+    (lib.mkRemovedOptionModule [
+      "services"
+      "hyperhive"
+      "snapshotStore"
+      "port"
+    ] snapshotStoreRemoved)
 
     # Same type, same meaning, new path — so a rename carries it exactly
     # and existing configs keep evaluating with one warning naming both