Manage the built-in daemon from one place in settings (#1938)

* feat(settings): consolidate daemon management into the host page

The app-level Daemon section and the localhost host page rendered the
same daemon card in two places. The host page is now the single home:
the Host sidebar group leads with Overview, and a desktop-only "Enable
built-in daemon" option in the host switcher recovers a removed
localhost connection. Old settings/daemon deep links redirect
(COMPAT-tagged).

* fix(settings): hide daemon recovery option when the server id probe fails

Review feedback: !query.isLoading treated an errored IPC probe as
resolved, so the recovery affordance could show without knowing the
local server id. Replace the resolved-boolean hook with a single
discriminated state hook (loading | error | resolved) — errors hide the
affordance and fall back to the settings root in the redirect. Also
collapses the two query subscriptions per caller into one.

* fix(settings): keep daemon recovery reachable when no hosts remain

Review feedback: removing localhost as the only host takes the settings
sidebar down its no-host branch, which never mounts the host picker —
so the "Enable built-in daemon" option was unreachable in the most
common recovery case. The sidebar now owns the single hook call, passes
it to the picker, and renders the same action as a sidebar row next to
"Add host" when no hosts exist.

* test(e2e): update settings host header to Overview

Test drift: the host section's sidebar/header label was intentionally
renamed to "Overview"; the spec still asserted the old "Host" title.
Also assert the retired app-level Daemon row stays absent.

packages/app/src/hooks/use-is-local-daemon.ts

@@ -15,10 +15,10 @@ async function loadDesktopDaemonServerId(): Promise<DesktopDaemonServerIdResult>
   };
 }
 
-export function useLocalDaemonServerId(): string | null {
+function useLocalDaemonServerIdQuery() {
   const isDesktopApp = shouldUseDesktopDaemon();
 
-  const query = useQuery({
+  return useQuery({
     queryKey: DESKTOP_DAEMON_SERVER_ID_QUERY_KEY,
     queryFn: loadDesktopDaemonServerId,
     enabled: isDesktopApp,
@@ -30,6 +30,11 @@ export function useLocalDaemonServerId(): string | null {
     refetchOnWindowFocus: false,
     retry: false,
   });
+}
+
+export function useLocalDaemonServerId(): string | null {
+  const isDesktopApp = shouldUseDesktopDaemon();
+  const query = useLocalDaemonServerIdQuery();
 
   if (!isDesktopApp) {
     return null;
@@ -38,6 +43,27 @@ export function useLocalDaemonServerId(): string | null {
   return query.data?.serverId ?? null;
 }
 
+export type LocalDaemonServerIdState =
+  | { status: "loading" }
+  | { status: "error" }
+  | { status: "resolved"; serverId: string | null };
+
+export function useLocalDaemonServerIdState(): LocalDaemonServerIdState {
+  const isDesktopApp = shouldUseDesktopDaemon();
+  const query = useLocalDaemonServerIdQuery();
+
+  if (!isDesktopApp) {
+    return { status: "resolved", serverId: null };
+  }
+  if (query.isError) {
+    return { status: "error" };
+  }
+  if (query.isSuccess) {
+    return { status: "resolved", serverId: query.data.serverId };
+  }
+  return { status: "loading" };
+}
+
 export function useIsLocalDaemon(serverId: string): boolean {
   const normalizedServerId = serverId.trim();
   const localServerId = useLocalDaemonServerId();