fix(core): token writes keep their actor in history but are user-owned in field_sources

fieldOwner(actor) maps every non-plugin actor to "user" wherever field_sources is written
(entries, engagements, list ownership from history), so syncs never overwrite a field an API
token edited. authenticateAppToken also returns the token name; revokeAppToken reports whether
it revoked; listSuggestions queries the canonical work id.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

packages/core/src/history.ts

@@ -12,6 +12,15 @@ import { restoreListFromHistory } from "./lists.ts";
 /** Who made a change. Plugin actors are `plugin:<pluginId>:<connectionId>`; API tokens are `token:<name>`. */
 export type Actor = "user" | `plugin:${string}:${string}` | `token:${string}`;
 
+/**
+ * Who owns a field in `field_sources` after `actor` writes it. Only plugin actors keep their name; the user,
+ * through the UI or an API token, is always `"user"`, so syncs never overwrite a field a script edited.
+ * History rows keep the full actor.
+ */
+export function fieldOwner(actor: string): string {
+  return actor.startsWith("plugin:") ? actor : "user";
+}
+
 /** User-layer entities that write `user_history`. */
 export type HistoryEntity = "entry" | "engagement" | "copy" | "list";