Add E2E testing infrastructure with WebdriverIO + Appium

Set up E2E test framework for Android using WebdriverIO, Appium, and
UiAutomator2. Add testID props to key components (AuthButton, BaseButton,
ChatBubble, CustomTextInput, ProposedEventCard) and apply testIDs to
login screen, chat screen, tab bar, and settings. Include initial tests
for app launch detection and login flow validation. Update CLAUDE.md
with E2E docs.

apps/client/src/app/(tabs)/_layout.tsx

@@ -19,6 +19,7 @@ export default function TabLayout() {
           name="chat"
           options={{
             title: "Chat",
+            tabBarTestID: "tab-chat",
             tabBarIcon: ({ color }) => (
               <Ionicons size={28} name="chatbubble" color={color} />
             ),
@@ -28,6 +29,7 @@ export default function TabLayout() {
           name="calendar"
           options={{
             title: "Calendar",
+            tabBarTestID: "tab-calendar",
             tabBarIcon: ({ color }) => (
               <Ionicons size={28} name="calendar" color={color} />
             ),
@@ -37,6 +39,7 @@ export default function TabLayout() {
           name="settings"
           options={{
             title: "Settings",
+            tabBarTestID: "tab-settings",
             tabBarIcon: ({ color }) => (
               <Ionicons size={28} name="settings" color={color} />
             ),

apps/client/src/app/(tabs)/chat.tsx

@@ -342,6 +342,7 @@ const ChatInput = ({ onSend }: ChatInputProps) => {
   return (
     <View className="flex flex-row w-full items-end my-2 px-2">
       <TextInput
+        testID="chat-message-input"
         className="flex-1 border border-solid rounded-2xl px-3 py-2 mr-2"
         style={{
           backgroundColor: theme.messageBorderBg,
@@ -356,7 +357,7 @@ const ChatInput = ({ onSend }: ChatInputProps) => {
         placeholderTextColor={theme.textMuted}
         multiline
       />
-      <Pressable onPress={handleSend}>
+      <Pressable testID="chat-send-button" onPress={handleSend}>
         <View
           className="w-10 h-10 rounded-full items-center justify-center"
           style={{
@@ -393,6 +394,7 @@ const ChatMessage = ({
   return (
     <ChatBubble
       side={side}
+      testID={`chat-bubble-${side}`}
       style={{
         maxWidth: "80%",
         minWidth: hasProposals ? "75%" : undefined,

apps/client/src/app/(tabs)/settings.tsx

@@ -20,6 +20,7 @@ const handleLogout = async () => {
 const SettingsButton = (props: BaseButtonProps) => {
   return (
     <BaseButton
+      testID={props.testID}
       onPress={props.onPress}
       solid={props.solid}
       className={"w-11/12"}
@@ -214,7 +215,7 @@ const Settings = () => {
     <BaseBackground>
       <SimpleHeader text="Settings" />
       <View className="flex items-center mt-4">
-        <SettingsButton onPress={handleLogout} solid={true}>
+        <SettingsButton testID="settings-logout-button" onPress={handleLogout} solid={true}>
           <Ionicons name="log-out-outline" size={24} color={theme.primeFg} />{" "}
           Logout
         </SettingsButton>

apps/client/src/app/login.tsx

@@ -45,6 +45,7 @@ const LoginScreen = () => {
     <BaseBackground>
       <View className="flex-1 justify-center items-center p-8">
         <Text
+          testID="login-title"
           className="text-3xl font-bold mb-8"
           style={{ color: theme.textPrimary }}
         >
@@ -53,6 +54,7 @@ const LoginScreen = () => {
 
         {error && (
           <Text
+            testID="login-error-text"
             className="mb-4 text-center"
             style={{ color: theme.rejectButton }}
           >
@@ -61,6 +63,7 @@ const LoginScreen = () => {
         )}
 
         <CustomTextInput
+          testID="login-identifier-input"
           placeholder="E-Mail oder Benutzername"
           placeholderTextColor={theme.textMuted}
           text={identifier}
@@ -70,6 +73,7 @@ const LoginScreen = () => {
         />
 
         <CustomTextInput
+          testID="login-password-input"
           placeholder="Passwort"
           placeholderTextColor={theme.textMuted}
           text={password}
@@ -79,6 +83,7 @@ const LoginScreen = () => {
         />
 
         <AuthButton
+          testID="login-button"
           title="Anmelden"
           onPress={handleLogin}
           isLoading={isLoading}