feat(characters): support character-scoped conversations

src/app/chat/chat-screen.tsx

@@ -52,6 +52,7 @@ export function ChatScreen() {
   const authState = useAuthState();
   const authDispatch = useAuthDispatch();
   useSplashLatestMessageSync({
+    characterId: state.characterId,
     historyLoaded: state.historyLoaded,
     loginStatus: authState.loginStatus,
     messages: state.historyMessages,
@@ -182,6 +183,7 @@ export function ChatScreen() {
           />
 
           <ChatArea
+            characterId={state.characterId}
             messages={visibleMessages}
             isReplyingAI={state.isReplyingAI}
             scrollToBottomSignal={state.outgoingMessageRevision}
@@ -220,6 +222,7 @@ export function ChatScreen() {
 
         {selectedImageMessage?.imageUrl ? (
           <FullscreenImageViewer
+            characterId={state.characterId}
             messageId={selectedImageMessage.id}
             imageUrl={selectedImageMessage.imageUrl}
             imagePaywalled={selectedImageMessage.imagePaywalled === true}