refactor(characters): drive shared UI from active character

src/stores/chat/chat-context.tsx

@@ -4,8 +4,6 @@ import { type Dispatch, type ReactNode, useMemo } from "react";
 import { createActorContext, shallowEqual } from "@xstate/react";
 import type { SnapshotFrom } from "xstate";
 
-import { DEFAULT_CHARACTER_ID } from "@/data/constants/character";
-
 import { chatMachine } from "./chat-machine";
 import type { ChatEvent, ChatState as MachineContext } from "./chat-machine";
 import { appendPromotionMessage } from "./helper/promotion";
@@ -46,15 +44,19 @@ const ChatActorContext = createActorContext(chatMachine);
 
 export interface ChatProviderProps {
   children: ReactNode;
-  characterId?: string;
+  characterId: string;
+  emptyChatGreeting: string;
 }
 
 export function ChatProvider({
   children,
-  characterId = DEFAULT_CHARACTER_ID,
+  characterId,
+  emptyChatGreeting,
 }: ChatProviderProps) {
   return (
-    <ChatActorContext.Provider options={{ input: { characterId } }}>
+    <ChatActorContext.Provider
+      options={{ input: { characterId, emptyChatGreeting } }}
+    >
       {children}
     </ChatActorContext.Provider>
   );