fix(keyboard): Android keyboard covers input — use react-native-keyboard-controller

Bug: 3 Stellen hatten `behavior={Platform.OS === 'ios' ? 'padding' : undefined}`.
Auf Android = `undefined` = KeyboardAvoidingView macht NICHTS → Input wird von
Tastatur verdeckt (chat-input, profile-edit-nickname, room-chat).

Fix: switch zu react-native-keyboard-controller's KeyboardAvoidingView mit
behavior='padding' für beide Plattformen. Funktioniert sauber cross-platform
weil KeyboardProvider schon im root-layout sitzt.

Affected Files:
- components/KeyboardAwareScreen.tsx (used by profile-edit + auth-screens)
- app/dm.tsx (DM chat)
- app/room.tsx (room chat)

lyra.tsx war bereits OK (`'height'` für Android — kein Fix nötig).

iOS-Verhalten unverändert.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

apps/rebreak-native/app/dm.tsx

@@ -4,12 +4,12 @@ import {
   Text,
   FlatList,
   TouchableOpacity,
-  KeyboardAvoidingView,
   Platform,
   ActivityIndicator,
   Image,
   StyleSheet,
 } from 'react-native';
+import { KeyboardAvoidingView } from 'react-native-keyboard-controller';
 import { SafeAreaView, useSafeAreaInsets } from 'react-native-safe-area-context';
 import { useRouter, useLocalSearchParams } from 'expo-router';
 import { Ionicons } from '@expo/vector-icons';
@@ -275,7 +275,7 @@ export default function DmScreen() {
 
       <KeyboardAvoidingView
         style={{ flex: 1 }}
-        behavior={Platform.OS === 'ios' ? 'padding' : undefined}
+        behavior="padding"
         keyboardVerticalOffset={0}
       >
         <View style={{ flex: 1, backgroundColor: chatBg }}>

apps/rebreak-native/app/room.tsx

@@ -9,12 +9,12 @@ import {
   Modal,
   TextInput,
   ActivityIndicator,
-  KeyboardAvoidingView,
   Platform,
   Alert,
   StyleSheet,
   ScrollView,
 } from 'react-native';
+import { KeyboardAvoidingView } from 'react-native-keyboard-controller';
 import { SafeAreaView, useSafeAreaInsets } from 'react-native-safe-area-context';
 import { useRouter, useLocalSearchParams } from 'expo-router';
 import { Ionicons } from '@expo/vector-icons';
@@ -360,7 +360,7 @@ export default function RoomScreen() {
       ) : (
         <KeyboardAvoidingView
           style={{ flex: 1 }}
-          behavior={Platform.OS === 'ios' ? 'padding' : undefined}
+          behavior="padding"
         >
           <FlatList
             ref={flatRef}

apps/rebreak-native/components/KeyboardAwareScreen.tsx

@@ -1,7 +1,6 @@
 import { ReactNode } from 'react';
 import {
   Keyboard,
-  KeyboardAvoidingView,
   Platform,
   ScrollView,
   StyleProp,
@@ -9,6 +8,7 @@ import {
   View,
   ViewStyle,
 } from 'react-native';
+import { KeyboardAvoidingView } from 'react-native-keyboard-controller';
 
 export interface KeyboardAwareScreenProps {
   children: ReactNode;
@@ -42,7 +42,7 @@ export function KeyboardAwareScreen({
   return (
     <KeyboardAvoidingView
       style={[{ flex: 1 }, style]}
-      behavior={Platform.OS === 'ios' ? 'padding' : undefined}
+      behavior="padding"
       keyboardVerticalOffset={headerOffset}
     >
       {scrollable ? (