Move /platform/detection vars into /env (#9707)

* Add platform vars to env

* Replace /platform/detection with /env

src/view/com/posts/CustomFeedEmptyState.tsx

@@ -13,9 +13,9 @@ import {MagnifyingGlassIcon} from '#/lib/icons'
 import {type NavigationProp} from '#/lib/routes/types'
 import {s} from '#/lib/styles'
 import {logger} from '#/logger'
-import {isWeb} from '#/platform/detection'
 import {useFeedFeedbackContext} from '#/state/feed-feedback'
 import {useSession} from '#/state/session'
+import {IS_WEB} from '#/env'
 import {Button} from '../util/forms/Button'
 import {Text} from '../util/text/Text'
 
@@ -44,7 +44,7 @@ export function CustomFeedEmptyState() {
   const navigation = useNavigation<NavigationProp>()
 
   const onPressFindAccounts = React.useCallback(() => {
-    if (isWeb) {
+    if (IS_WEB) {
       navigation.navigate('Search', {})
     } else {
       navigation.navigate('SearchTab')