feat(app): the module registry drives the render (S6b DoD)

Replace App's page-render ternary and the three side-rail page conditionals with
a data-driven lookup: components/moduleRegistry maps each page to a prop-free
content component (+ optional side rail + shell fadeTop), and App renders
PAGE_CONTENT[page]/PAGE_RAIL[page] gated by moduleDef(page).gate (an unreachable
gated page falls back to the feed, as the old ternary did). Content modules and
the two rails are now prop-free: they read `me` via the new useMe() hook and
their module-local state from the scoped providers; FeedPage/MessagesPage are the
only wrappers (they wire the global feed scope / meId). App.tsx 796->431 lines,
zero `page===X` chrome conditionals — closes the Platform epic DoD. (Platform S6b.3)

frontend/src/App.tsx

@@ -9,6 +9,7 @@ import {
 } from "./lib/api";
 import { setLanguage, isSupported, type LangCode } from "./i18n";
 import { hasFilterParams, stripUrlParams } from "./lib/urlState";
+import type { Page } from "./lib/urlState";
 import {
   loadLayout,
   normalizeLayout,
@@ -27,13 +28,13 @@ import {
 import { useNavigation, useNavigationActions } from "./components/NavigationProvider";
 import { useFeedFilters, useFeedFiltersActions } from "./components/FeedFiltersProvider";
 import { useFeedView, useFeedViewActions } from "./components/FeedViewProvider";
+import { moduleDef } from "./lib/modules";
+import { PAGE_CONTENT, PAGE_RAIL } from "./components/moduleRegistry";
 // Persistent shell — always mounted, so eagerly imported.
 import Welcome from "./components/Welcome";
 import SetupWizard from "./components/SetupWizard";
 import Header from "./components/Header";
 import NavSidebar from "./components/NavSidebar";
-import Sidebar from "./components/Sidebar";
-import PlaylistsRail from "./components/PlaylistsRail";
 import BackToTop from "./components/BackToTop";
 import PageShell from "./components/PageShell";
 import GlassTuner from "./components/GlassTuner";
@@ -45,31 +46,17 @@ import DemoBanner from "./components/DemoBanner";
 import { focusAccessRequestsTab } from "./lib/adminUsersTab";
 import { CURRENT_VERSION } from "./lib/releaseNotes";
 
-// Route-level code splitting: each module page (and the heavier modals) is its own lazy chunk,
+// The page modules (and their side rails) are code-split per route via the module registry
-// so the initial load — and the logged-out landing — pulls only the shell, and admin-only pages
+// (components/moduleRegistry). App keeps only the persistent-shell chunks + the channel page and the
-// never reach non-admins. All are rendered inside a <Suspense> boundary below.
+// two modals, which sit outside the registry-driven content column.
-const Feed = lazy(() => import("./components/Feed"));
-const PlexBrowse = lazy(() => import("./components/PlexBrowse"));
-const PlexSidebar = lazy(() => import("./components/PlexSidebar"));
 const ChannelPage = lazy(() => import("./components/ChannelPage"));
-const Channels = lazy(() => import("./components/Channels"));
-const Playlists = lazy(() => import("./components/Playlists"));
-const Stats = lazy(() => import("./components/Stats"));
-const Scheduler = lazy(() => import("./components/Scheduler"));
-const ConfigPanel = lazy(() => import("./components/ConfigPanel"));
-const AdminUsers = lazy(() => import("./components/AdminUsers"));
-const AuditLog = lazy(() => import("./components/AuditLog"));
-const SettingsPanel = lazy(() => import("./components/SettingsPanel"));
-const NotificationsPanel = lazy(() => import("./components/NotificationsPanel"));
-const Messages = lazy(() => import("./components/Messages"));
-const DownloadCenter = lazy(() => import("./components/DownloadCenter"));
 const About = lazy(() => import("./components/About"));
 const ReleaseNotes = lazy(() => import("./components/ReleaseNotes"));
 
 export default function App() {
   const { t, i18n } = useTranslation();
   const { page, channelView, ytSearch } = useNavigation();
-  const { setPage, enterYtSearch, exitYtSearch } = useNavigationActions();
+  const { setPage, enterYtSearch } = useNavigationActions();
   // The global feed filters live in FeedFiltersProvider (per-account persistence + the account-load
   // effect + share-link capture all moved there). App reads them to hand to <Feed> and to the
   // handlers that mutate the feed view (onShowInFeed, tag-click, the feed scrollKey).
@@ -331,6 +318,16 @@ export default function App() {
         ? `yt:${ytSearch}`
         : `feed:${JSON.stringify({ ...filters, q: "" })}`;
 
+  // The module registry drives the render from `page` alone — no per-page chrome conditionals. A
+  // page the account can't reach (a gated module via stale nav / a deep link) falls back to the feed,
+  // exactly as the old ternary's fallthrough did. A channel page overlays the content column, so no
+  // side rail shows behind it.
+  const me = meQuery.data!;
+  const pageGate = moduleDef(page).gate;
+  const activePage: Page = !pageGate || pageGate(me) ? page : "feed";
+  const { Component: PageContent, fadeTop } = PAGE_CONTENT[activePage];
+  const railDef = channelView ? undefined : PAGE_RAIL[activePage];
+
   return (
     <div className="h-screen flex text-fg">
       <NavSidebar
@@ -341,36 +338,23 @@ export default function App() {
         collapsed={navCollapsed}
         onToggleCollapse={() => setNavCollapsed(!navCollapsed)}
       />
-      {/* Full-height filter sidebar: feed only, and hidden while a channel page overlays the
+      {/* The active page's side rail (feed filters / plex filters / playlists list), if it has one.
-          content column. Sits beside the nav rail as its own collapsible column. */}
+          A floating collapsible column beside the nav rail; hidden while a channel page overlays the
-      {page === "feed" && !channelView && (
+          content. feed + plex share the filter-rail collapse flag, playlists has its own. */}
-        <Sidebar
+      {railDef && (
-          layout={panelLayouts.feed}
-          setLayout={(l) => setPanelLayout("feed", l)}
-          isDemo={meQuery.data!.is_demo}
-          collapsed={filterCollapsed}
-          onToggleCollapse={() => setFilterCollapsed(!filterCollapsed)}
-        />
-      )}
-      {page === "plex" && meQuery.data!.plex_enabled && (
         <Suspense fallback={null}>
-          <PlexSidebar
+          <railDef.Rail
-            layout={panelLayouts.plex}
+            layout={panelLayouts[railDef.panelId]}
-            setLayout={(l) => setPanelLayout("plex", l)}
+            setLayout={(l) => setPanelLayout(railDef.panelId, l)}
-            collapsed={filterCollapsed}
+            collapsed={railDef.collapse === "playlists" ? playlistsCollapsed : filterCollapsed}
-            onToggleCollapse={() => setFilterCollapsed(!filterCollapsed)}
+            onToggleCollapse={() =>
+              railDef.collapse === "playlists"
+                ? setPlaylistsCollapsed(!playlistsCollapsed)
+                : setFilterCollapsed(!filterCollapsed)
+            }
           />
         </Suspense>
       )}
-      {page === "playlists" && !channelView && (
-        <PlaylistsRail
-          me={meQuery.data!}
-          layout={panelLayouts.playlists}
-          setLayout={(l) => setPanelLayout("playlists", l)}
-          collapsed={playlistsCollapsed}
-          onToggleCollapse={() => setPlaylistsCollapsed(!playlistsCollapsed)}
-        />
-      )}
       <div className="relative flex-1 min-w-0 flex flex-col">
         {channelView ? (
           <PageShell scrollKey={`channel:${channelView.id}`}>
@@ -403,12 +387,8 @@ export default function App() {
         ) : (
           <PageShell
             scrollKey={normalScrollKey}
-            // Channels + Audit render a table with a sticky header at the scroller top; the top
+            fadeTop={fadeTop ?? true}
-            // fade would sit on it and flip on with the first scroll, so turn it off there.
+            header={<Header me={meQuery.data!} onYtSearch={enterYtSearch} />}
-            fadeTop={page !== "channels" && page !== "audit"}
-            header={
-              <Header me={meQuery.data!} onYtSearch={enterYtSearch} />
-            }
             banners={
               <>
                 {meQuery.data!.is_demo && <DemoBanner />}
@@ -417,45 +397,7 @@ export default function App() {
             }
           >
           <Suspense fallback={pageFallback}>
-          {page === "channels" ? (
+            <PageContent />
-            <Channels me={meQuery.data!} />
-          ) : page === "stats" ? (
-            <Stats me={meQuery.data!} />
-          ) : page === "scheduler" && meQuery.data!.role === "admin" ? (
-            <Scheduler />
-          ) : page === "config" && meQuery.data!.role === "admin" ? (
-            <ConfigPanel />
-          ) : page === "users" && meQuery.data!.role === "admin" ? (
-            <AdminUsers me={meQuery.data!} />
-          ) : page === "audit" && meQuery.data!.role === "admin" ? (
-            <AuditLog />
-          ) : page === "playlists" ? (
-            <Playlists me={meQuery.data!} />
-          ) : page === "notifications" ? (
-            <NotificationsPanel />
-          ) : page === "messages" && !meQuery.data!.is_demo ? (
-            <div className="p-4 max-w-3xl w-full mx-auto">
-              <Messages meId={meQuery.data!.id} />
-            </div>
-          ) : page === "downloads" && !meQuery.data!.is_demo ? (
-            <DownloadCenter me={meQuery.data!} />
-          ) : page === "settings" ? (
-            <SettingsPanel me={meQuery.data!} />
-          ) : page === "plex" && meQuery.data!.plex_enabled ? (
-            <PlexBrowse />
-          ) : (
-            <Feed
-              filters={filters}
-              setFilters={setFilters}
-              view={view}
-              setView={setView}
-              canRead={meQuery.data!.can_read}
-              isDemo={meQuery.data!.is_demo}
-              ytSearch={ytSearch}
-              onYtSearch={enterYtSearch}
-              onExitYtSearch={exitYtSearch}
-            />
-          )}
           </Suspense>
           </PageShell>
         )}

frontend/src/components/AdminUsers.tsx

@@ -10,6 +10,7 @@ import { Section } from "./ui/form";
 import { useConfirm } from "./ConfirmProvider";
 import Tabs, { usePersistedTab } from "./Tabs";
 import { PageToolbar } from "./PageShell";
+import { useMe } from "../lib/useMe";
 
 // Admin-only user & access management: roles, access requests (the Invite whitelist), and the
 // demo whitelist + reset. Each section is its own tab (persisted across reloads); the Access tab
@@ -17,7 +18,8 @@ import { PageToolbar } from "./PageShell";
 // (The tab key + a "focus the Access tab" helper live in lib/adminUsersTab so callers can
 // pre-select the tab without importing this lazy-loaded page — see that file.)
 
-export default function AdminUsers({ me }: { me: Me }) {
+export default function AdminUsers() {
+  const me = useMe();
   const { t } = useTranslation();
   const [tab, setTab] = usePersistedTab(ADMIN_USERS_TAB_KEY, "roles");
   const tabs = [

frontend/src/components/Channels.tsx

@@ -15,7 +15,7 @@ import {
   UserMinus,
   X,
 } from "lucide-react";
-import { api, type ManagedChannel, type Me, type Tag } from "../lib/api";
+import { api, type ManagedChannel, type Tag } from "../lib/api";
 import { notifyYouTubeActionError } from "../lib/youtubeErrors";
 import { accountKey, LS } from "../lib/storage";
 import { useDismiss } from "../lib/useDismiss";
@@ -34,6 +34,7 @@ import { useChannels, useChannelsActions } from "./ChannelsProvider";
 import { useNavigationActions } from "./NavigationProvider";
 import { useFeedFilters, useFeedFiltersActions } from "./FeedFiltersProvider";
 import { useWizard } from "./WizardProvider";
+import { useMe } from "../lib/useMe";
 
 export type ChannelsView = "subscribed" | "discovery" | "blocked";
 
@@ -46,7 +47,8 @@ const STATUS_FILTERS: { id: ChannelStatusFilter; labelKey: string }[] = [
   { id: "hidden", labelKey: "channels.filters.hidden" },
 ];
 
-export default function Channels({ me }: { me: Me }) {
+export default function Channels() {
+  const me = useMe();
   const canWrite = me.can_write;
   const isAdmin = me.role === "admin";
   // "Connect YouTube" onboarding lives in WizardProvider (a notify action / a mutation-error CTA).

frontend/src/components/DownloadCenter.tsx

@@ -27,7 +27,8 @@ const VideoEditor = lazy(() => import("./VideoEditor"));
 const ShareDialog = lazy(() => import("./ShareDialog"));
 import { useConfirm } from "./ConfirmProvider";
 import { useLiveQuery } from "../lib/useLiveQuery";
-import { api, type DownloadJob, type Me } from "../lib/api";
+import { useMe } from "../lib/useMe";
+import { api, type DownloadJob } from "../lib/api";
 import { invalidateDownloads } from "../lib/downloads";
 import { notify } from "../lib/notifications";
 import { formatBytes, formatDuration, formatEta, formatSpeed } from "../lib/format";
@@ -539,7 +540,8 @@ function AdminSystem() {
 
 // --- Main -----------------------------------------------------------------------------------
 
-export default function DownloadCenter({ me }: { me: Me }) {
+export default function DownloadCenter() {
+  const me = useMe();
   const { t } = useTranslation();
   const qc = useQueryClient();
   const confirm = useConfirm();

frontend/src/components/Playlists.tsx

@@ -31,7 +31,7 @@ import {
   X,
   Youtube,
 } from "lucide-react";
-import { api, type Me, type Video } from "../lib/api";
+import { api, type Video } from "../lib/api";
 import { formatDuration } from "../lib/format";
 import { notify } from "../lib/notifications";
 import { notifyYouTubeActionError } from "../lib/youtubeErrors";
@@ -41,6 +41,7 @@ import UndoToolbar from "./UndoToolbar";
 import { PageToolbar } from "./PageShell";
 import { useConfirm } from "./ConfirmProvider";
 import { usePlaylists, usePlaylistsActions } from "./PlaylistsProvider";
+import { useMe } from "../lib/useMe";
 
 type SortKey = "manual" | "title" | "duration" | "channel";
 type SortDir = "asc" | "desc";
@@ -179,7 +180,8 @@ function Row({
   );
 }
 
-export default function Playlists({ me }: { me: Me }) {
+export default function Playlists() {
+  const me = useMe();
   const canWrite = me.can_write;
   // The selected playlist lives in PlaylistsProvider, shared with the PlaylistsRail (which owns the
   // list + its rail controls). This detail pane reacts to the selection.

frontend/src/components/PlaylistsRail.tsx

@@ -2,7 +2,7 @@ import { useEffect, useMemo, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import { useMutation, useQuery, useQueryClient } from "@tanstack/react-query";
 import { ArrowDown, ArrowUp, ListVideo, Pin, Plus, RefreshCw, Youtube } from "lucide-react";
-import { api, type Me, type Playlist } from "../lib/api";
+import { api, type Playlist } from "../lib/api";
 import { formatDuration } from "../lib/format";
 import { notify } from "../lib/notifications";
 import { notifyYouTubeActionError } from "../lib/youtubeErrors";
@@ -11,6 +11,7 @@ import { defaultLayout, type PanelLayout } from "../lib/panelLayout";
 import SidePanel from "./SidePanel";
 import PanelGroups, { type PanelItem } from "./PanelGroups";
 import { usePlaylists, usePlaylistsActions } from "./PlaylistsProvider";
+import { useMe } from "../lib/useMe";
 
 type PlSort = { key: "custom" | "name" | "count" | "duration"; dir: "asc" | "desc"; dirtyFirst: boolean };
 const PL_SORT_DEFAULT: PlSort = { key: "custom", dir: "asc", dirtyFirst: false };
@@ -20,19 +21,17 @@ const PL_SORT_DEFAULT: PlSort = { key: "custom", dir: "asc", dirtyFirst: false }
 // controls (sort / new / sync); the selected playlist is App state so the module's detail pane
 // (Playlists.tsx) reacts to it. Grouped into two islands: "manage" and the playlist list.
 export default function PlaylistsRail({
-  me,
   layout,
   setLayout,
   collapsed,
   onToggleCollapse,
 }: {
-  me: Me;
   layout: PanelLayout;
   setLayout: (l: PanelLayout) => void;
   collapsed: boolean;
   onToggleCollapse: () => void;
 }) {
-  const canWrite = me.can_write;
+  const canWrite = useMe().can_write;
   // The name filter + the selected playlist live in PlaylistsProvider (shared with the header search
   // box and the Playlists detail pane); this rail owns the list query + its own controls.
   const { search, selectedId } = usePlaylists();

frontend/src/components/SettingsPanel.tsx

@@ -13,6 +13,7 @@ import { type SaveState } from "./ui/DraftSaveBar";
 import { useConfirm } from "./ConfirmProvider";
 import { useWizard } from "./WizardProvider";
 import { usePrefs } from "./PrefsProvider";
+import { useMe } from "../lib/useMe";
 
 // The Settings page edits server-persisted preferences. Each change applies locally for instant
 // preview AND auto-saves (debounced) — no draft, no Save button; a small indicator flashes the
@@ -41,7 +42,8 @@ const TABS: { id: TabId; icon: typeof Monitor }[] = [
 // Settings as a page (Design B): rendered in the main content area, not an overlay. It keeps
 // the frosted `.glass` surface so it still refracts the ambient backdrop. The page title is
 // shown by the Header; the tab rail stays as in-page sub-navigation.
-export default function SettingsPanel({ me }: { me: Me }) {
+export default function SettingsPanel() {
+  const me = useMe();
   const { t } = useTranslation();
   // The editable prefs (theme/perf/hints/notifications + save state) live in PrefsProvider.
   const prefs = usePrefs();

frontend/src/components/Sidebar.tsx

@@ -15,6 +15,7 @@ import PanelGroups, { type PanelItem } from "./PanelGroups";
 import ChannelPicker from "./ChannelPicker";
 import { useFeedFilters, useFeedFiltersActions } from "./FeedFiltersProvider";
 import { useChannelsActions } from "./ChannelsProvider";
+import { useMe } from "../lib/useMe";
 
 // Filter ids; display labels resolved at render time via t("sidebar.sort.<id>") etc.
 const DATE_PRESETS: { days: number; key: string }[] = [
@@ -64,17 +65,16 @@ function TagChip({
 export default function Sidebar({
   layout,
   setLayout,
-  isDemo = false,
   collapsed,
   onToggleCollapse,
 }: {
   layout: PanelLayout;
   setLayout: (l: PanelLayout) => void;
-  isDemo?: boolean;
   collapsed: boolean;
   onToggleCollapse: () => void;
 }) {
   const { t } = useTranslation();
+  const isDemo = useMe().is_demo;
   const filters = useFeedFilters();
   const { setFilters } = useFeedFiltersActions();
   // "Focus this channel in the manager" (from the tag manager here) lives in ChannelsProvider.

frontend/src/components/Stats.tsx

@@ -8,6 +8,7 @@ import { notify } from "../lib/notifications";
 import { LS, useAccountPersistedState } from "../lib/storage";
 import Tooltip from "./Tooltip";
 import { Section, SettingRow } from "./ui/form";
+import { useMe } from "../lib/useMe";
 
 const RANGES = [7, 30, 90] as const;
 type StatsTab = "overview" | "system";
@@ -15,7 +16,8 @@ type StatsTab = "overview" | "system";
 // Usage & stats page. "Overview" is per-user (sync status + your own API usage + actions);
 // "System" is the admin-only instance-wide quota dashboard + background-sync control. The
 // per-user content used to live in Settings → Sync; it moved here so Settings stays config-only.
-export default function Stats({ me }: { me: Me }) {
+export default function Stats() {
+  const me = useMe();
   const { t } = useTranslation();
   const isAdmin = me.role === "admin";
   const [tabRaw, setTab] = useAccountPersistedState(LS.statsTab, "overview");

frontend/src/components/moduleRegistry.tsx

@@ -0,0 +1,121 @@
+import { lazy, type ComponentType } from "react";
+import type { Page } from "../lib/urlState";
+import type { PanelId, PanelLayout } from "../lib/panelLayout";
+import { useMe } from "../lib/useMe";
+import { useFeedFilters, useFeedFiltersActions } from "./FeedFiltersProvider";
+import { useFeedView, useFeedViewActions } from "./FeedViewProvider";
+import { useNavigation, useNavigationActions } from "./NavigationProvider";
+import Sidebar from "./Sidebar";
+import PlaylistsRail from "./PlaylistsRail";
+
+// The RENDER half of the module registry: which component (and side rail) each page renders. The
+// metadata half — nav order, label, icon, gate — lives in lib/modules.ts (imported by NavSidebar /
+// Header / App's gate check). Together they let App drive the whole shell from `page` alone, with no
+// `page === X` chrome conditionals.
+//
+// Every content entry is a PROP-FREE component: it reads `me` from useMe() and its module-local state
+// from the scoped providers, so App renders `<Content />` uniformly. The two that need per-render
+// wiring get a thin wrapper here (FeedPage supplies the GLOBAL feed scope; the channel page threads
+// its own isolated scope to <Feed> directly — see the scope note in FeedFiltersProvider).
+
+// Route-level code splitting: each page is its own lazy chunk (admin-only pages never reach
+// non-admins; the logged-out landing pulls only the shell). Rendered inside App's <Suspense>.
+const Feed = lazy(() => import("./Feed"));
+const Channels = lazy(() => import("./Channels"));
+const Playlists = lazy(() => import("./Playlists"));
+const PlexBrowse = lazy(() => import("./PlexBrowse"));
+const PlexSidebar = lazy(() => import("./PlexSidebar"));
+const NotificationsPanel = lazy(() => import("./NotificationsPanel"));
+const Messages = lazy(() => import("./Messages"));
+const DownloadCenter = lazy(() => import("./DownloadCenter"));
+const Stats = lazy(() => import("./Stats"));
+const Scheduler = lazy(() => import("./Scheduler"));
+const ConfigPanel = lazy(() => import("./ConfigPanel"));
+const AdminUsers = lazy(() => import("./AdminUsers"));
+const AuditLog = lazy(() => import("./AuditLog"));
+const SettingsPanel = lazy(() => import("./SettingsPanel"));
+
+// The GLOBAL feed page: wires <Feed> to the app-wide feed filters / view / live-search. (The channel
+// page renders <Feed> itself with its own channel-scoped filters, so those two never share state.)
+function FeedPage() {
+  const me = useMe();
+  const filters = useFeedFilters();
+  const { setFilters } = useFeedFiltersActions();
+  const view = useFeedView();
+  const { setView } = useFeedViewActions();
+  const { ytSearch } = useNavigation();
+  const { enterYtSearch, exitYtSearch } = useNavigationActions();
+  return (
+    <Feed
+      filters={filters}
+      setFilters={setFilters}
+      view={view}
+      setView={setView}
+      canRead={me.can_read}
+      isDemo={me.is_demo}
+      ytSearch={ytSearch}
+      onYtSearch={enterYtSearch}
+      onExitYtSearch={exitYtSearch}
+    />
+  );
+}
+
+function MessagesPage() {
+  const me = useMe();
+  return (
+    <div className="p-4 max-w-3xl w-full mx-auto">
+      <Messages meId={me.id} />
+    </div>
+  );
+}
+
+export type PageDef = {
+  // Prop-free by construction: reads `me` + module state from hooks/providers.
+  Component: ComponentType;
+  // Channels + Audit render a table with a sticky header at the scroller top; the shell's top fade
+  // would sit on it and flip on with the first scroll, so they turn it off. Defaults to on.
+  fadeTop?: boolean;
+};
+
+// page id → the component App renders in the content column (+ its shell chrome config).
+export const PAGE_CONTENT: Record<Page, PageDef> = {
+  feed: { Component: FeedPage },
+  channels: { Component: Channels, fadeTop: false },
+  playlists: { Component: Playlists },
+  plex: { Component: PlexBrowse },
+  notifications: { Component: NotificationsPanel },
+  messages: { Component: MessagesPage },
+  downloads: { Component: DownloadCenter },
+  stats: { Component: Stats },
+  scheduler: { Component: Scheduler },
+  config: { Component: ConfigPanel },
+  users: { Component: AdminUsers },
+  audit: { Component: AuditLog, fadeTop: false },
+  settings: { Component: SettingsPanel },
+};
+
+// The uniform side-rail contract — shell layout/collapse only; the rail reads its module state from
+// its provider and `me` from useMe().
+type RailProps = {
+  layout: PanelLayout;
+  setLayout: (l: PanelLayout) => void;
+  collapsed: boolean;
+  onToggleCollapse: () => void;
+};
+
+// Which collapse flag a rail uses (feed + plex share the filter rail's flag; playlists has its own).
+type RailCollapseKey = "filter" | "playlists";
+
+export type RailDef = {
+  Rail: ComponentType<RailProps>;
+  // The persisted panel-layout record this rail edits (App owns the panelLayouts map).
+  panelId: PanelId;
+  collapse: RailCollapseKey;
+};
+
+// page id → its side rail (only the three pages that have one). App renders it in the rail slot.
+export const PAGE_RAIL: Partial<Record<Page, RailDef>> = {
+  feed: { Rail: Sidebar, panelId: "feed", collapse: "filter" },
+  plex: { Rail: PlexSidebar, panelId: "plex", collapse: "filter" },
+  playlists: { Rail: PlaylistsRail, panelId: "playlists", collapse: "playlists" },
+};

frontend/src/lib/useMe.ts

@@ -0,0 +1,13 @@
+import { useQuery } from "@tanstack/react-query";
+import { api, type Me } from "./api";
+
+// The signed-in account, read from the ["me"] query cache. App owns the FETCHING query (gated on
+// setup state) and renders modules only once it has resolved to a real user — so anywhere inside the
+// authenticated module tree the cache is always populated. `enabled:false` makes this a passive
+// observer (no second fetch, which could 503 in setup mode) that still re-renders when the cache
+// updates (login, the 60s refetch, a Google-link round-trip). Lets modules read `me` from a hook
+// instead of having it prop-drilled through App.
+export function useMe(): Me {
+  const { data } = useQuery({ queryKey: ["me"], queryFn: api.me, enabled: false });
+  return data as Me;
+}