Keep Android chat controls above the keyboard

apps/mobile/App.tsx

@@ -3,7 +3,15 @@
 // app, NOT the Ungoogled Chromium engine — see docs/mobile-architecture.md.
 import { StatusBar } from 'expo-status-bar';
 import { useState, type ReactNode } from 'react';
-import { Keyboard, StyleSheet, Text, TouchableOpacity, View } from 'react-native';
+import {
+  Keyboard,
+  KeyboardAvoidingView,
+  Platform,
+  StyleSheet,
+  Text,
+  TouchableOpacity,
+  View,
+} from 'react-native';
 import { SafeAreaProvider, useSafeAreaInsets } from 'react-native-safe-area-context';
 import { BrowserScreen } from './src/screens/BrowserScreen';
 import { ChatScreen } from './src/screens/ChatScreen';
@@ -57,7 +65,12 @@ function AppShell() {
   const insets = useSafeAreaInsets();
 
   return (
-    <View
+    <KeyboardAvoidingView
+      // Edge-to-edge Android windows do not reliably resize the absolute tab
+      // scenes for the IME. Resize their shared root, including the tab bar.
+      enabled={Platform.OS === 'android'}
+      behavior={Platform.OS === 'android' ? 'height' : undefined}
+      keyboardVerticalOffset={0}
       style={[
         styles.root,
         { paddingTop: insets.top, paddingLeft: insets.left, paddingRight: insets.right },
@@ -98,7 +111,7 @@ function AppShell() {
           );
         })}
       </View>
-    </View>
+    </KeyboardAvoidingView>
   );
 }
 

apps/mobile/test/keyboard.test.tsx

@@ -0,0 +1,42 @@
+import { describe, expect, it } from 'vitest';
+import App from '../App';
+import { flat, hosts, renderScreen, scenes, tabButton } from './harness';
+import { Platform } from './mocks/react-native';
+import { setMockSafeAreaInsets } from './mocks/react-native-safe-area-context';
+
+// Native geometry is exercised separately with the APK. These tests pin the
+// platform wiring so mocked native components cannot claim to prove IME layout.
+describe('shell keyboard avoidance', () => {
+  it('resizes the Android shell containing the scenes and tabs', async () => {
+    const renderer = await renderScreen(<App />);
+    const shell = hosts(renderer.root, 'KeyboardAvoidingView').find(
+      (node) => node.props.enabled === true,
+    );
+    expect(shell).toBeDefined();
+    expect(shell!.props.behavior).toBe('height');
+    expect(shell!.props.keyboardVerticalOffset).toBe(0);
+    expect(scenes(shell!)).toHaveLength(4);
+    expect(tabButton(shell!, 'Chat')).toBeDefined();
+  });
+
+  it('keeps system insets inside the keyboard-aware root without a second offset', async () => {
+    setMockSafeAreaInsets({ top: 37, right: 12, bottom: 48, left: 12 });
+    const renderer = await renderScreen(<App />);
+    const shell = hosts(renderer.root, 'KeyboardAvoidingView').find(
+      (node) => node.props.enabled === true,
+    );
+    expect(shell).toBeDefined();
+    expect(flat(shell!)).toMatchObject({ paddingTop: 37, paddingLeft: 12, paddingRight: 12 });
+    expect(shell!.props.keyboardVerticalOffset).toBe(0);
+  });
+
+  it('does not add a second keyboard adjustment to the existing iOS chat', async () => {
+    Platform.OS = 'ios';
+    const renderer = await renderScreen(<App />);
+    const views = hosts(renderer.root, 'KeyboardAvoidingView');
+    const shell = views.find((node) => node.props.enabled === false);
+    expect(shell).toBeDefined();
+    expect(shell!.props.behavior).toBeUndefined();
+    expect(views.some((node) => node.props.behavior === 'padding')).toBe(true);
+  });
+});

apps/mobile/test/safe-area.test.tsx

@@ -11,7 +11,7 @@ import { setMockSafeAreaInsets } from './mocks/react-native-safe-area-context';
 
 import type { ReactTestInstance } from 'react-test-renderer';
 
-const shellRoot = (root: ReactTestInstance) => hosts(root, 'View')[0];
+const shellRoot = (root: ReactTestInstance) => hosts(root, 'KeyboardAvoidingView')[0];
 
 const tabBar = (root: ReactTestInstance) =>
   hostWhere(