refactor(core): move ZIndexContext to singletons

packages/sanity/src/_singletons/components/zOffsets/ZIndexContext.ts

@@ -0,0 +1,11 @@
+import {createContext} from 'react'
+import type {ZIndexContextValue} from 'sanity'
+
+import {zIndexContextDefaults} from './zIndexContextDefaults'
+
+/**
+ * TODO: Rename to `ZOffsetsContext`
+ *
+ * @internal
+ */
+export const ZIndexContext = createContext<ZIndexContextValue>(zIndexContextDefaults)

packages/sanity/src/core/components/zOffsets/defaults.ts → packages/sanity/src/_singletons/components/zOffsets/zIndexContextDefaults.ts

@@ -1,9 +1,9 @@
-import {type ZIndexContextValue} from './types'
+import type {ZIndexContextValue} from 'sanity'
 
 /**
  * @internal
  */
-export const defaults: ZIndexContextValue = {
+export const zIndexContextDefaults: ZIndexContextValue = {
   navbar: 200,
   navbarPopover: 500000,
   navbarDialog: 500001,

packages/sanity/src/_singletons/index.ts

@@ -1,3 +1,5 @@
 export * from './changeIndicators/ConnectorContext'
 export * from './components/previewCard/PreviewCardContext'
 export * from './components/scroll/scrollContext'
+export * from './components/zOffsets/ZIndexContext'
+export * from './components/zOffsets/zIndexContextDefaults'

packages/sanity/src/core/components/zOffsets/ZIndexProvider.tsx

@@ -1,13 +1,11 @@
 import {type ReactElement, type ReactNode} from 'react'
-
-import {defaults} from './defaults'
-import {ZIndexContext} from './ZIndexContext'
+import {ZIndexContext, zIndexContextDefaults} from 'sanity/_singletons'
 
 /**
  * TODO: Rename to `ZOffsetsProvider`
  *
  * @internal
  */
 export function ZIndexProvider({children}: {children?: ReactNode}): ReactElement {
-  return <ZIndexContext.Provider value={defaults}>{children}</ZIndexContext.Provider>
+  return <ZIndexContext.Provider value={zIndexContextDefaults}>{children}</ZIndexContext.Provider>
 }

packages/sanity/src/core/components/zOffsets/useZIndex.ts

@@ -1,7 +1,7 @@
 import {useContext} from 'react'
+import {ZIndexContext} from 'sanity/_singletons'
 
 import {type ZIndexContextValue} from './types'
-import {ZIndexContext} from './ZIndexContext'
 
 /**
  * TODO: Rename to `useZOffsets`