Add a Schedules screen to manage recurring agents (#1246)

* feat: add Schedules screen to manage scheduled agents

Adds a Schedules section in the sidebar header (below Sessions) for viewing
and managing new-agent schedules: recurring jobs that spawn an agent on a
cron or interval cadence.

- Borderless table showing provider icon, model, cadence, next run, and
  status, with row actions to edit, pause/resume, run now, and delete.
- Create/edit sheet that reuses the agent provider/model/mode/working-
  directory pickers, plus an interval/cron cadence editor with presets,
  validation, and a UTC preview.
- Responsive: hover-revealed row actions on desktop, an always-visible
  action menu on mobile.
- Data layer over the existing schedule RPCs (list/create/update/pause/
  resume/delete/run-once) with optimistic pause, resume, and delete.

Scope is limited to new-agent schedules for now.

* Make the schedule form controls visually consistent

Merge the provider and model pickers into the single nested selector the
draft screen uses, render it as a full-width field, mute the placeholder,
proportion the cadence segmented controls, unify the cron preset chips,
and route the sheet scroll through the themed scrollbar.

* Address schedules review feedback

* Translate schedule hook client fallback errors

* Make schedules global and project scoped

* Stabilize project settings transport E2E

* Reset schedule model on cross-host project change

* Reject malformed cron step expressions

* Tighten schedules project query freshness

* refactor(schedules): clean up review feedback

* test(schedules): extract fake host setup

* refactor(schedules): share cron expression parsing

Use one structural cron parser for app previews and daemon cadence validation so the accepted grammar cannot drift between surfaces.

Remove the unused host-scoped schedules redirect while keeping the global schedules route.

packages/app/src/hooks/use-projects.ts

@@ -1,4 +1,4 @@
-import { useMemo } from "react";
+import { useMemo, useSyncExternalStore } from "react";
 import { useQuery } from "@tanstack/react-query";
 import { getHostRuntimeStore, useHosts } from "@/runtime/host-runtime";
 import type { ProjectSummary } from "@/utils/projects";
@@ -16,6 +16,10 @@ export type {
 
 export const projectsQueryKey = ["projects"] as const;
 
+function projectsQueryRuntimeKey(hosts: readonly ProjectsHostInput[]) {
+  return hosts.map((host) => host.serverId).join("|");
+}
+
 export interface UseProjectsResult {
   projects: ProjectSummary[];
   hostErrors: ProjectHostError[];
@@ -27,6 +31,11 @@ export interface UseProjectsResult {
 export function useProjects(): UseProjectsResult {
   const hosts = useHosts();
   const runtime = getHostRuntimeStore();
+  const runtimeVersion = useSyncExternalStore(
+    (onStoreChange) => runtime.subscribeAll(onStoreChange),
+    () => runtime.getVersion(),
+    () => runtime.getVersion(),
+  );
   const hostInputs = useMemo<ProjectsHostInput[]>(
     () =>
       hosts.map((host) => ({
@@ -37,8 +46,9 @@ export function useProjects(): UseProjectsResult {
   );
 
   const projectsQuery = useQuery({
-    queryKey: projectsQueryKey,
+    queryKey: [...projectsQueryKey, projectsQueryRuntimeKey(hostInputs), runtimeVersion] as const,
     queryFn: () => fetchAggregatedProjects({ hosts: hostInputs, runtime }),
+    staleTime: 5_000,
   });
 
   return {