test: add stable test ids to sign-in fields, tabs and message rows

src/screens/EmailListScreen.tsx

@@ -176,6 +176,7 @@ const EmailRow = React.memo(function EmailRow({
       onPress={handlePress}
       onLongPress={handleLongPress}
       delayLongPress={300}
+      testID="email-row"
     >
       {unread && (
         <View

src/screens/login/PasswordStep.tsx

@@ -61,6 +61,7 @@ export default function PasswordStep({
         placeholder={t('login.username_placeholder', 'user@example.com')}
         value={email}
         onChangeText={onChangeEmail}
+        testID="login-username-input"
         autoCapitalize="none"
         autoCorrect={false}
         autoComplete="email"
@@ -76,6 +77,7 @@ export default function PasswordStep({
         placeholder={t('login.password_placeholder', 'Enter your password')}
         value={password}
         onChangeText={onChangePassword}
+        testID="login-password-input"
         autoFocus={Boolean(email)}
         secureTextEntry={!showPassword}
         autoComplete="current-password"

src/screens/login/ServerStep.tsx

@@ -61,6 +61,7 @@ export default function ServerStep({
       <Input
         label={t('login.mobile.server_label', 'Server address')}
         placeholder="mail.example.com"
+        testID="login-server-input"
         value={value}
         onChangeText={onChange}
         autoFocus