Addressing review feedback: tidy nav-item types and shared map

- Move LeftNavItem type declaration below the import block in LeftNav.tsx
    (it was wedged between two imports).
  - Extract the identical Home/Search/Messages/Notifications/MyProfile ->
    nav-item maps from BottomBar.tsx and Drawer.tsx into a single
    src/lib/routes/tab-to-nav-item.ts.

src/lib/routes/tab-to-nav-item.ts

@@ -0,0 +1,17 @@
+export type SharedNavTab =
+  | 'Home'
+  | 'Search'
+  | 'Messages'
+  | 'Notifications'
+  | 'MyProfile'
+
+export const TAB_TO_NAV_ITEM: Record<
+  SharedNavTab,
+  'home' | 'search' | 'chat' | 'notifications' | 'profile'
+> = {
+  Home: 'home',
+  Search: 'search',
+  Messages: 'chat',
+  Notifications: 'notifications',
+  MyProfile: 'profile',
+}

src/view/shell/Drawer.tsx

@@ -10,6 +10,7 @@ import {FEEDBACK_FORM_URL, HELP_DESK_URL} from '#/lib/constants'
 import {type PressableScale} from '#/lib/custom-animations/PressableScale'
 import {useNavigationTabState} from '#/lib/hooks/useNavigationTabState'
 import {getTabState, TabState} from '#/lib/routes/helpers'
+import {type SharedNavTab, TAB_TO_NAV_ITEM} from '#/lib/routes/tab-to-nav-item'
 import {type NavigationProp} from '#/lib/routes/types'
 import {sanitizeHandle} from '#/lib/strings/handles'
 import {colors} from '#/lib/styles'
@@ -134,24 +135,6 @@ let DrawerProfileCard = ({
 DrawerProfileCard = memo(DrawerProfileCard)
 export {DrawerProfileCard}
 
-type DrawerTabOption =
-  | 'Home'
-  | 'Search'
-  | 'Messages'
-  | 'Notifications'
-  | 'MyProfile'
-
-const DRAWER_TAB_TO_NAV_ITEM: Record<
-  DrawerTabOption,
-  'home' | 'search' | 'chat' | 'notifications' | 'profile'
-> = {
-  Home: 'home',
-  Search: 'search',
-  Messages: 'chat',
-  Notifications: 'notifications',
-  MyProfile: 'profile',
-}
-
 let DrawerContent = ({}: React.PropsWithoutRef<{}>): React.ReactNode => {
   const t = useTheme()
   const insets = useSafeAreaInsets()
@@ -173,9 +156,9 @@ let DrawerContent = ({}: React.PropsWithoutRef<{}>): React.ReactNode => {
   // =
 
   const onPressTab = useCallback(
-    (tab: DrawerTabOption, surface: 'drawer' | 'drawerHeader' = 'drawer') => {
+    (tab: SharedNavTab, surface: 'drawer' | 'drawerHeader' = 'drawer') => {
       ax.metric('nav:click', {
-        item: DRAWER_TAB_TO_NAV_ITEM[tab],
+        item: TAB_TO_NAV_ITEM[tab],
         surface,
       })
       const state = navigation.getState()

src/view/shell/bottom-bar/BottomBar.tsx

@@ -17,6 +17,7 @@ import {useMinimalShellFooterTransform} from '#/lib/hooks/useMinimalShellTransfo
 import {useNavigationTabState} from '#/lib/hooks/useNavigationTabState'
 import {clamp} from '#/lib/numbers'
 import {getTabState, TabState} from '#/lib/routes/helpers'
+import {type SharedNavTab, TAB_TO_NAV_ITEM} from '#/lib/routes/tab-to-nav-item'
 import {emitSoftReset} from '#/state/events'
 import {useUnreadMessageCount} from '#/state/queries/messages/list-conversations'
 import {useUnreadNotifications} from '#/state/queries/notifications/unread'
@@ -55,19 +56,6 @@ import {useActorStatus} from '#/features/liveNow'
 import {useDemoMode} from '#/storage/hooks/demo-mode'
 import {styles} from './BottomBarStyles'
 
-type TabOptions = 'Home' | 'Search' | 'Messages' | 'Notifications' | 'MyProfile'
-
-const TAB_TO_NAV_ITEM: Record<
-  TabOptions,
-  'home' | 'search' | 'chat' | 'notifications' | 'profile'
-> = {
-  Home: 'home',
-  Search: 'search',
-  Messages: 'chat',
-  Notifications: 'notifications',
-  MyProfile: 'profile',
-}
-
 export function BottomBar({navigation}: BottomTabBarProps) {
   const {hasSession, currentAccount} = useSession()
   const t = useTheme()
@@ -102,7 +90,7 @@ export function BottomBar({navigation}: BottomTabBarProps) {
   }, [requestSwitchToAccount, closeAllActiveElements])
 
   const onPressTab = useCallback(
-    (tab: TabOptions) => {
+    (tab: SharedNavTab) => {
       ax.metric('nav:click', {
         item: TAB_TO_NAV_ITEM[tab],
         surface: 'bottomBar',

src/view/shell/desktop/LeftNav.tsx

@@ -86,6 +86,7 @@ import {useAgeAssurance} from '#/ageAssurance'
 import {useAnalytics} from '#/analytics'
 import {useActorStatus} from '#/features/liveNow'
 import {router} from '#/routes'
+import {PlatformInfo} from '../../../../modules/expo-bluesky-swiss-army'
 
 type LeftNavItem =
   | 'home'
@@ -97,7 +98,6 @@ type LeftNavItem =
   | 'saved'
   | 'profile'
   | 'settings'
-import {PlatformInfo} from '../../../../modules/expo-bluesky-swiss-army'
 
 const LARGE_ELEMENT_SIZE = 48
 const NAV_ICON_WIDTH = 28