chore: review suggestions for #3759 (#3790)

## Description

Applies review suggestions raised on #3759. Changes are kept in a
separate branch to allow incremental review before squashing/merging
into the target.

## Changes

- `initialFocusedName` → `defaultRouteName`: clearer name that avoids
"focused" terminology inconsistent with the rest of the API; JSDoc
comment updated accordingly
- Remove unused `TabsContainerWithDynamicRouteConfigs`,
`TabsRouteConfigContext`, and `useTabsRouteConfigContext` — no call
sites found in the codebase

## Test plan

Verify that tab selection works correctly in the example app on both iOS
and Android, and that the `defaultRouteName` prop correctly sets the
initially selected tab.

## Checklist

- [ ] Included code example that can be used to test this change.
- [ ] Updated / created local changelog entries in relevant test files.
- [ ] For visual changes, included screenshots / GIFs / recordings
documenting the change.
- [x] For API changes, updated relevant public types.
- [ ] Ensured that CI passes

---------

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: kkafar

apps/src/shared/gamma/containers/tabs/TabsContainer.tsx

@@ -31,7 +31,7 @@ export function TabsContainer(props: TabsContainerProps) {
 
   const {
     routeConfigs,
-    initialFocusedName,
+    defaultRouteName,
     experimentalControlNavigationStateInJS,
     onTabSelected,
     ...restProps
@@ -44,7 +44,7 @@ export function TabsContainer(props: TabsContainerProps) {
     React.Dispatch<TabsNavigationAction>,
   ] = React.useReducer(
     tabsNavigationReducerWithLogging,
-    { routeConfigs, initialFocusedName },
+    { routeConfigs, defaultRouteName },
     determineInitialTabsContainerState,
   );
 

apps/src/shared/gamma/containers/tabs/TabsContainer.types.tsx

@@ -87,10 +87,10 @@ export type TabsContainerProps = Omit<
 > & {
   routeConfigs: TabRouteConfig[];
   /**
-   * Name of the tab that should be focused initially.
+   * Name of the tab that should be selected initially.
    * Defaults to the first tab if not provided.
    */
-  initialFocusedName?: string;
+  defaultRouteName?: string;
   /**
    * Whether to control navigation state in JS.
    * Passed to Tabs.Host as experimentalControlNavigationStateInJS.

apps/src/shared/gamma/containers/tabs/TabsContainerWithDynamicRouteConfigs.tsx

@@ -19,7 +19,7 @@ import {
 export function TabsContainerWithHostConfigContext(props: TabsContainerProps) {
   const {
     routeConfigs,
-    initialFocusedName,
+    defaultRouteName,
     experimentalControlNavigationStateInJS,
     ...hostProps
   } = props;
@@ -42,7 +42,7 @@ export function TabsContainerWithHostConfigContext(props: TabsContainerProps) {
     <TabsHostConfigContext value={tabsHostConfigContext}>
       <TabsContainer
         routeConfigs={routeConfigs}
-        initialFocusedName={initialFocusedName}
+        defaultRouteName={defaultRouteName}
         experimentalControlNavigationStateInJS={
           experimentalControlNavigationStateInJS
         }

apps/src/shared/gamma/containers/tabs/TabsContainerWithHostConfigContext.tsx

@@ -13,13 +13,10 @@ export type {
 
 export type { TabsNavigationContextPayload } from './contexts/TabsNavigationContext';
 export type { TabsHostConfigContextPayload } from './contexts/TabsHostConfigContext';
-export type { TabsRouteConfigContextPayload } from './contexts/TabsRouteConfigContext';
 
 export { useTabsNavigationContext } from './hooks/useTabsNavigationContext';
 export { useTabsHostConfig } from './hooks/useTabsHostConfig';
-export { useTabsRouteConfigContext } from './hooks/useTabsRouteConfigContext';
 
 export { TabsContainer } from './TabsContainer';
-export { TabsContainerWithDynamicRouteConfigs } from './TabsContainerWithDynamicRouteConfigs';
 export { TabsContainerWithHostConfigContext } from './TabsContainerWithHostConfigContext';
 export { DEFAULT_TAB_ROUTE_OPTIONS } from './presets';

apps/src/shared/gamma/containers/tabs/contexts/TabsRouteConfigContext.tsx

@@ -147,22 +147,22 @@ function createTabRouteFromConfig(config: TabRouteConfig): TabRoute {
 
 export type TabsContainerStateInitArg = {
   routeConfigs: TabRouteConfig[];
-  initialFocusedName?: string;
+  defaultRouteName?: string;
 };
 
 export function determineInitialTabsContainerState(
   arg: TabsContainerStateInitArg,
 ): TabsContainerState {
-  const { routeConfigs, initialFocusedName } = arg;
+  const { routeConfigs, defaultRouteName } = arg;
 
   const routes = routeConfigs.map(createTabRouteFromConfig);
 
   let selectedRouteKey: string;
-  if (initialFocusedName != null) {
-    const matchingRoute = routes.find(r => r.name === initialFocusedName);
-    if (matchingRoute == null) {
+  if (defaultRouteName != null) {
+    const matchingRoute = routes.find(r => r.name === defaultRouteName);
+    if (!matchingRoute) {
       throw new Error(
-        `[Tabs] initialFocusedName "${initialFocusedName}" does not match any route config name`,
+        `[Tabs] defaultRouteName "${defaultRouteName}" does not match any route config name`,
       );
     }
     selectedRouteKey = matchingRoute.routeKey;

apps/src/shared/gamma/containers/tabs/hooks/useTabsRouteConfigContext.tsx

@@ -278,7 +278,7 @@ function App() {
       }}>
       <TabsContainer
         routeConfigs={TAB_CONFIGS}
-        initialFocusedName="Tab1"
+        defaultRouteName="Tab1"
         ios={{
           tabBarTintColor: Colors.YellowLight100,
           tabBarMinimizeBehavior: 'onScrollDown',

apps/src/shared/gamma/containers/tabs/index.ts

@@ -201,7 +201,7 @@ function ScreenStackTabs() {
 
   return (
     <NavigationIndependentTree>
-      <TabsContainer initialFocusedName="Auto" routeConfigs={routeConfigs} />
+      <TabsContainer defaultRouteName="Auto" routeConfigs={routeConfigs} />
     </NavigationIndependentTree>
   );
 }