Account switcher (#85)

* Update the account-create and signin views to use the design system.

Also:
- Add borderDark to the theme
- Start to an account selector in the signin flow

* Dark mode fixes in signin ui

* Track multiple active accounts and provide account-switching UI

* Add test tooling for an in-memory pds

* Add complete integration tests for login and the account switcher

src/view/shell/mobile/Menu.tsx

@@ -62,7 +62,7 @@ export const Menu = observer(
       onPress?: () => void
     }) => (
       <TouchableOpacity
-        testID="menuItemButton"
+        testID={`menuItemButton-${label}`}
         style={styles.menuItem}
         onPress={onPress ? onPress : () => onNavigate(url || '/')}>
         <View style={[styles.menuItemIconWrapper]}>

src/view/shell/mobile/index.tsx

@@ -5,7 +5,6 @@ import {
   Easing,
   FlatList,
   GestureResponderEvent,
-  SafeAreaView,
   StatusBar,
   StyleSheet,
   TouchableOpacity,
@@ -16,7 +15,6 @@ import {
   ViewStyle,
 } from 'react-native'
 import {ScreenContainer, Screen} from 'react-native-screens'
-import LinearGradient from 'react-native-linear-gradient'
 import {useSafeAreaInsets} from 'react-native-safe-area-context'
 import {FontAwesomeIcon} from '@fortawesome/react-native-fontawesome'
 import {IconProp} from '@fortawesome/fontawesome-svg-core'
@@ -34,7 +32,7 @@ import {Text} from '../../com/util/text/Text'
 import {ErrorBoundary} from '../../com/util/ErrorBoundary'
 import {TabsSelector} from './TabsSelector'
 import {Composer} from './Composer'
-import {s, colors} from '../../lib/styles'
+import {colors} from '../../lib/styles'
 import {clamp} from '../../../lib/numbers'
 import {
   GridIcon,
@@ -323,18 +321,10 @@ export const MobileShell: React.FC = observer(() => {
 
   if (!store.session.hasSession) {
     return (
-      <LinearGradient
-        colors={['#007CFF', '#00BCFF']}
-        start={{x: 0, y: 0.8}}
-        end={{x: 0, y: 1}}
-        style={styles.outerContainer}>
-        <SafeAreaView testID="noSessionView" style={styles.innerContainer}>
-          <ErrorBoundary>
-            <Login />
-          </ErrorBoundary>
-        </SafeAreaView>
+      <View style={styles.outerContainer}>
+        <Login />
         <Modal />
-      </LinearGradient>
+      </View>
     )
   }
   if (store.onboard.isOnboarding) {