v4: a user from another instance can't be renamed from their profile's manage tab — it offered the name field to every user, and the API refuses a remote one's rename with a 400, since their home names them. The tab now only shows their name, as the settings do for one's own.

The profile's and the settings' tests of a remote account's links to its home still expected the home's host itself, which 8bcc005 replaced with GET /api/users/:key/home; they now expect that.

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

src/components/profile/ProfileManageTab.tsx

@@ -13,6 +13,7 @@ import type { PublicUser } from "../../../shared/user.ts";
 import { expectOk } from "../../utils/shared/api.ts";
 import { deserializePublicUser } from "../../utils/shared/deserialize.ts";
 import { useAuth } from "../../hooks/auth/useAuth.ts";
+import { homeHost } from "../../utils/auth/home.ts";
 import { ProfileSection } from "./ProfileSection.tsx";
 import { RoleSwitcher } from "./RoleSwitcher.tsx";
 import { SettingRow } from "./SettingRow.tsx";
@@ -30,7 +31,8 @@ export interface ProfileManageTabProps {
 
 /**
  * Renders the user's role and name. A rename here has no rate limit, and the
- * profile's URL then takes the new name.
+ * profile's URL then takes the new name. A user from another instance is
+ * named there, so their name is only shown.
  */
 export function ProfileManageTab(
   { user, onUserSaved }: ProfileManageTabProps,
@@ -59,11 +61,15 @@ export function ProfileManageTab(
           onSaved={(role) => onUserSaved({ ...user, role })}
         />
         <SettingRow label={<Trans>Username</Trans>}>
-          <UsernameField
-            key={user.username}
-            username={user.username}
-            save={rename}
-          />
+          {homeHost(user.username)
+            ? <span className="profile-appearance-value">{user.username}</span>
+            : (
+              <UsernameField
+                key={user.username}
+                username={user.username}
+                save={rename}
+              />
+            )}
         </SettingRow>
       </div>
     </ProfileSection>