fix(chat): Listen-Spinner-Hänger + Auto-Scroll bei Bild-Nachrichten

Bug 1 — Chat-Liste: RefreshControl nutzte React-Querys `isRefetching`,
das bei JEDEM Background-Refetch (focus-/stale-getriggert) true wird →
nach Zurück-Navigation hing der Pull-to-Refresh-Spinner endlos. Fix:
eigener `userRefreshing`-State, nur bei explizitem Pull-to-Refresh true,
im finally zurückgesetzt.

Bug 2 — Conversation scrollte nicht bis zur letzten Nachricht, wenn die
ein Bild war: onContentSizeChange-scrollToEnd feuerte vor dem Bild-Load.
Fix: ChatBubble bekommt onImageLoad-Callback, die letzte Bild-Nachricht
triggert nach dem Laden erneut scrollToBottom.

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

apps/rebreak-native/app/(app)/chat.tsx

@@ -94,11 +94,11 @@ export default function ChatScreen() {
   const colors = useColors();
   const styles = makeStyles(colors);
   const [search, setSearch] = useState('');
+  const [userRefreshing, setUserRefreshing] = useState(false);
 
   const {
     data: convs = [],
     isLoading: loadingDms,
-    isRefetching: refetchingDms,
     refetch: refetchDms,
   } = useQuery<DmConversation[]>({
     queryKey: ['dm-conversations'],
@@ -106,6 +106,15 @@ export default function ChatScreen() {
     staleTime: 30_000,
   });
 
+  const handleRefresh = useCallback(async () => {
+    setUserRefreshing(true);
+    try {
+      await refetchDms();
+    } finally {
+      setUserRefreshing(false);
+    }
+  }, [refetchDms]);
+
   const filtered = search.trim()
     ? convs.filter((c) =>
         c.partnerName.toLowerCase().includes(search.toLowerCase()) ||
@@ -152,8 +161,8 @@ export default function ChatScreen() {
         keyExtractor={(item) => item.partnerId}
         refreshControl={
           <RefreshControl
-            refreshing={refetchingDms}
+            refreshing={userRefreshing}
-            onRefresh={refetchDms}
+            onRefresh={handleRefresh}
             tintColor={colors.brandOrange}
           />
         }

apps/rebreak-native/app/dm.tsx

@@ -93,6 +93,7 @@ export default function DmScreen() {
     setPartner(null);
     partnerRef.current = null;
     setReplyTo(null);
+    isInitialLoad.current = true;
   }, [userId]);
 
   // Lade DM-History — staleTime:0 erzwingt immer frischen Fetch (kein Cache-Hit-Bug)
@@ -174,12 +175,20 @@ export default function DmScreen() {
   );
   useDmRealtime(userId, onDmInsert, !!myUserId);
 
+  const isInitialLoad = useRef(true);
+
+  const scrollToBottom = useCallback((animated: boolean) => {
+    setTimeout(() => flatRef.current?.scrollToEnd({ animated }), 80);
+  }, []);
+
   // Auto-Scroll bei neuen Messages
   useEffect(() => {
     if (messages.length > 0) {
-      requestAnimationFrame(() => flatRef.current?.scrollToEnd({ animated: true }));
+      const animated = !isInitialLoad.current;
+      isInitialLoad.current = false;
+      scrollToBottom(animated);
     }
-  }, [messages.length]);
+  }, [messages.length, scrollToBottom]);
 
   async function handleSend(payload: SendPayload) {
     if (sending) return;
@@ -310,12 +319,12 @@ export default function DmScreen() {
                   onReply={startReply}
                   onLike={toggleLike}
                   onOpenImage={() => {}}
+                  onImageLoad={index === messages.length - 1 ? () => scrollToBottom(false) : undefined}
                 />
               )}
               keyExtractor={(m) => m.id}
               contentContainerStyle={{ paddingTop: 12, paddingBottom: 8 }}
               showsVerticalScrollIndicator={false}
-              onContentSizeChange={() => flatRef.current?.scrollToEnd({ animated: false })}
             />
           )}
         </View>

apps/rebreak-native/components/chat/ChatBubble.tsx

@@ -47,6 +47,7 @@ type Props = {
   onReply: (msg: ChatMsg) => void;
   onLike: (msg: ChatMsg) => void;
   onOpenImage: (url: string) => void;
+  onImageLoad?: () => void;
 };
 
 function formatTime(ts: string) {
@@ -75,6 +76,7 @@ export function ChatBubble({
   onReply,
   onLike,
   onOpenImage,
+  onImageLoad,
 }: Props) {
   const { t } = useTranslation();
   const colors = useColors();
@@ -201,6 +203,7 @@ export function ChatBubble({
                   contentFit="cover"
                   cachePolicy="memory-disk"
                   transition={200}
+                  onLoad={onImageLoad ? () => onImageLoad() : undefined}
                 />
                 {isImageOnly && (
                   <View style={styles.imageTimeOverlay}>