refactor!: replace Zustand global store with TanStack Query for systemFeatures

Follow-up to SSR prefetch migration (2833965). Eliminates the Zustand
middleman that was syncing TanStack Query data into a separate store.

- Remove useGlobalPublicStore Zustand store entirely
- Create hooks/use-global-public.ts with useSystemFeatures,
  useSystemFeaturesQuery, useIsSystemFeaturesPending, useSetupStatusQuery
- Migrate all 93 consumers to import from @/hooks/use-global-public
- Simplify global-public-context.tsx to a thin provider component
- Update 18 test files to mock the new hook interface
- Fix SetupStatusResponse.setup_at type from Date to string (JSON)
- Fix setup-status.spec.ts mock target to match consoleClient

BREAKING CHANGE: useGlobalPublicStore is removed. Use useSystemFeatures()
from @/hooks/use-global-public instead.

web/contract/console/system.ts

@@ -1,3 +1,4 @@
+import type { SetupStatusResponse } from '@/models/common'
 import type { SystemFeatures } from '@/types/feature'
 import { type } from '@orpc/contract'
 import { base } from '../base'
@@ -9,3 +10,11 @@ export const systemFeaturesContract = base
   })
   .input(type<unknown>())
   .output(type<SystemFeatures>())
+
+export const setupStatusContract = base
+  .route({
+    path: '/setup',
+    method: 'GET',
+  })
+  .input(type<unknown>())
+  .output(type<SetupStatusResponse>())