feat: open What's new from the Update Checker instead of the user menu

It sits beside the version an admin checks rather than in every user's menu; members still get it from the update notification.

docs/DEVELOPMENT.md

@@ -259,7 +259,7 @@ ordinary notification (the System tab). To post one, add an entry to `entries` a
 ## Release notes (What's new)
 
 The first time a backend starts on a newer version than it last ran, every user gets a notification that opens
-the What's new dialog (also in the user menu). A fresh install isn't told. There's no need to add a "Welcome to
+the What's new dialog (admins can reopen it from Update Checker in Administration). A fresh install isn't told. There's no need to add a "Welcome to
 X.Y.Z" entry to `system-notifications.json` for this any more.
 
 The dialog fetches its content from `main`, so it can be written after the release is out:

frontend/src/components/Layout/UserMenu.tsx

@@ -15,7 +15,6 @@ import PersonIcon from "@mui/icons-material/Person";
 import ViewInArIcon from "@mui/icons-material/ViewInAr";
 import SettingsIcon from "@mui/icons-material/Settings";
 import LogoutIcon from "@mui/icons-material/Logout";
-import NewReleasesOutlinedIcon from "@mui/icons-material/NewReleasesOutlined";
 import type { AuthUser } from "../../api/auth";
 import type { ConfigurationTab } from "./ConfigurationDialog";
 import { IMPORT_PROVIDER_INFO } from "../../constants/importProviders";
@@ -25,7 +24,6 @@ import { useGravatarUrl } from "../../hooks/useGravatarUrl";
 import { settingsApi, type Cults3dSettings } from "../../api/settings";
 import { cults3dReady, cults3dStatus } from "./ConfigurationDialog/cults3dStatus";
 import { useDisabledProviders } from "../../hooks/useDisabledProviders";
-import { useWhatsNew } from "../whatsNew/WhatsNewProvider";
 
 type ServiceChipDef = {
   key:
@@ -57,7 +55,6 @@ type Props = {
 export function UserMenu({ user, onOpenConfiguration, onOpenProfile, onLogout }: Props) {
   const { t } = useTranslation(["app", "common"]);
   const navigate = useNavigate();
-  const openWhatsNew = useWhatsNew();
   const avatarUrl = useGravatarUrl(user?.email, 128);
   const [anchorEl, setAnchorEl] = React.useState<HTMLElement | null>(null);
   const [makerworldConfigured, setMakerworldConfigured] = React.useState(false);
@@ -312,17 +309,6 @@ export function UserMenu({ user, onOpenConfiguration, onOpenProfile, onLogout }:
           </ListItemIcon>
           <ListItemText>{t("configuration.title")}</ListItemText>
         </MenuItem>
-        <MenuItem
-          onClick={() => {
-            closeMenu();
-            openWhatsNew();
-          }}
-        >
-          <ListItemIcon>
-            <NewReleasesOutlinedIcon fontSize="small" />
-          </ListItemIcon>
-          <ListItemText>{t("whatsNew.label")}</ListItemText>
-        </MenuItem>
         <Divider />
         <Box sx={{ px: 1.5, py: 1, display: "flex", flexWrap: "wrap", gap: 0.5, maxWidth: 260 }}>
           {services.map((svc) => (

frontend/src/pages/AdminPage/UpdateCheckSection.tsx

@@ -7,11 +7,14 @@ import CircularProgress from "@mui/material/CircularProgress";
 import Alert from "@mui/material/Alert";
 import AlertTitle from "@mui/material/AlertTitle";
 import Box from "@mui/material/Box";
+import Button from "@mui/material/Button";
+import NewReleasesOutlinedIcon from "@mui/icons-material/NewReleasesOutlined";
 import { UnauthorizedError } from "../../api/client";
 import { settingsApi, FRONTEND_GIT_SHA, FRONTEND_VERSION } from "../../api/settings";
 import SectionHeader from "../../components/SectionHeader";
 import { AnimatedTile } from "../../components/storageAnimations/parts";
 import UpdateCheckAnimation, { type UpdateCheckState } from "../../components/adminAnimations/UpdateCheckAnimation";
+import { useWhatsNew } from "../../components/whatsNew/WhatsNewProvider";
 
 type Props = {
   onUnauthorized?: () => void;
@@ -37,6 +40,7 @@ export default function UpdateCheckSection({ onUnauthorized }: Props) {
   const { t } = useTranslation("app");
   const [status, setStatus] = React.useState<Status>({ kind: "checking" });
   const [backendVersion, setBackendVersion] = React.useState<string | null>(null);
+  const openWhatsNew = useWhatsNew();
 
   React.useEffect(() => {
     let active = true;
@@ -72,6 +76,11 @@ export default function UpdateCheckSection({ onUnauthorized }: Props) {
       <SectionHeader
         title={t("adminSettings.updateCheck.heading")}
         subtitle={t("adminSettings.updateCheck.subtitle")}
+        actions={
+          <Button variant="outlined" startIcon={<NewReleasesOutlinedIcon />} onClick={() => openWhatsNew()}>
+            {t("whatsNew.label")}
+          </Button>
+        }
       />
       <Paper variant="outlined" sx={{ p: 2.5 }}>
         <Stack direction="row" spacing={2.5} alignItems="center">

release-notes/latest-release-notes.json

@@ -65,7 +65,7 @@
     {
       "type": "feature",
       "title": "What's new after every update",
-      "description": "You're reading it. Open it again any time from your user menu."
+      "description": "You're reading it. Admins can open it again any time from Update Checker in Administration."
     },
     {
       "type": "improvement",