feat(client): getOwnerInstanceForDm — route owner-only DM ops to current owner instance

packages/web/src/stores/spaceStore.ts

@@ -10,6 +10,7 @@ import {
   resolveUserIdFromInstances,
   getCachedUserIdForOrigin,
   clearMyUserIdCache,
+  setOwnerInstanceForDmResolver,
 } from '../utils/crossStoreResolvers';
 import { useAuthStore } from './authStore';
 import { useChatStore } from './chatStore';
@@ -1137,6 +1138,28 @@ export function getChannelOrigin(channelId: string): string {
   return useSpaceStore.getState().channelOriginMap.get(channelId) ?? '';
 }
 
+/**
+ * Returns the owner's home-instance origin for a group DM, or '' for the
+ * local home instance. Used to route owner-only API calls (rename, icon,
+ * kick, transfer) so the federation event's sourceInstance equals the
+ * channel's ownerHomeInstance — required by receiver authority checks.
+ *
+ * Distinct from getChannelOrigin: that function returns the channel's
+ * pinned serving origin (where the client's WS connection mirrors the
+ * channel), which can differ from the owner's home instance after a
+ * manual transfer.
+ *
+ * The resolver itself lives in `utils/crossStoreResolvers.ts` so that
+ * `api/client.ts` can call it without creating a value-cycle on spaceStore;
+ * spaceStore registers the resolver below at module load.
+ */
+export function getOwnerInstanceForDm(channelId: string): string {
+  const dm = useSpaceStore.getState().dmChannels.find(d => d.id === channelId);
+  return dm?.ownerHomeInstance ?? '';
+}
+
+setOwnerInstanceForDmResolver(getOwnerInstanceForDm);
+
 /**
  * Resolves a raw DM channel ID to its primary `dmChannels` entry ID.
  *