fix(desktop): setup cards stop redrawing in a loop

useSetupRows built a new row array on every render for the app-owned
lists (accent, layout, theme). That recreated the card's stage callback,
whose effect wrote $setupChooseStages, which re-rendered the card. The
rows are memoized on their inputs now, and stageSetupChoose skips the
atom write when a patch changes nothing.

apps/desktop/src/components/assistant-ui/clarify/setup-rows.ts

@@ -1,4 +1,5 @@
 import type { ConnectorRow, SetupChooseKind, SetupChooseOption } from '@hermes/shared'
+import { useMemo } from 'react'
 
 import { MODE_OPTIONS } from '@/app/settings/constants'
 import { $chatLayoutPicked, assembleChatOnboarding, snapshotChatLayout } from '@/components/onboarding-chat/assembly'
@@ -132,15 +133,20 @@ export function useSetupRows(setup: null | SetupChooseSpec, storedId: null | str
   const connectors = useConnectorRows(setup?.options === null && setup.kind === 'connectors' ? storedId : null)
   const plugins = useOnboardingPluginList(setup?.options === null && setup.kind === 'plugins' ? storedId : null)
 
-  if (!setup) {
-    return []
-  }
+  // Same inputs must return the same array: the pending card's stage callback and store write key off it.
+  return useMemo(() => {
+    if (!setup) {
+      return NO_ROWS
+    }
 
-  const rows = setup.options ?? APP_ROWS[setup.kind]({ connectors, dark: renderedMode === 'dark', plugins, t })
+    const rows = setup.options ?? APP_ROWS[setup.kind]({ connectors, dark: renderedMode === 'dark', plugins, t })
 
-  return setup.kind === 'theme' && rows ? rows.filter(row => THEME_TILES.includes(row.id)) : rows
+    return setup.kind === 'theme' && rows ? rows.filter(row => THEME_TILES.includes(row.id)) : rows
+  }, [connectors, plugins, renderedMode, setup, t])
 }
 
+const NO_ROWS: SetupRow[] = []
+
 export function useSetupLabel(
   kind: SetupChooseKind,
   options: null | SetupRow[],

apps/desktop/src/store/clarify.test.ts

@@ -181,6 +181,21 @@ describe('answerSetupCard', () => {
     expect(hasClarifyRequest('session-a')).toBe(false)
     expect(look).toBe('#0000ff')
   })
+
+  it('does not notify subscribers when a staged patch changes nothing', () => {
+    const preview = () => undefined
+    const listener = vi.fn()
+
+    stageSetupChoose('req-a', { labels: ACCENTS, preview })
+    const before = $setupChooseStages.get()
+    const unlisten = $setupChooseStages.listen(listener)
+
+    stageSetupChoose('req-a', { labels: ACCENTS, preview })
+    unlisten()
+
+    expect($setupChooseStages.get()).toBe(before)
+    expect(listener).not.toHaveBeenCalled()
+  })
 })
 
 describe('normalizeChoices', () => {

apps/desktop/src/store/clarify.ts

@@ -283,7 +283,19 @@ export const setupChooseStage = (requestId: string): SetupChooseStage =>
   $setupChooseStages.get()[requestId] ?? EMPTY_SETUP_STAGE
 
 export function stageSetupChoose(requestId: string, patch: Partial<SetupChooseStage>): void {
-  $setupChooseStages.set({ ...$setupChooseStages.get(), [requestId]: { ...setupChooseStage(requestId), ...patch } })
+  const current = setupChooseStage(requestId)
+
+  // A no-op patch keeps the atom reference so subscribers do not rerender.
+  const unchanged = Object.entries(patch).every(([key, value]) =>
+    // SAFETY: the entries of a Partial<SetupChooseStage> carry only SetupChooseStage keys.
+    Object.is(current[key as keyof SetupChooseStage], value)
+  )
+
+  if (unchanged && requestId in $setupChooseStages.get()) {
+    return
+  }
+
+  $setupChooseStages.set({ ...$setupChooseStages.get(), [requestId]: { ...current, ...patch } })
 }
 
 export function commitSetupChoose(requestId: string): void {