feat(characters): support character-scoped conversations

src/stores/chat/chat-state.ts

@@ -2,6 +2,7 @@ import type { UiMessage } from "@/data/dto/chat";
 import type { PendingChatUnlockKind } from "@/lib/navigation/chat_unlock_session";
 import type { ChatLockType } from "@/data/schemas/chat";
 import type { PendingChatPromotion } from "@/data/storage/navigation";
+import { DEFAULT_CHARACTER_ID } from "@/data/constants/character";
 import type { ChatPromotionState } from "./helper/promotion";
 
 export type ChatUpgradeReason = "insufficient_credits";
@@ -24,6 +25,7 @@ export interface ChatUnlockPaywallRequest
 }
 
 export interface ChatState {
+  characterId: string;
   messages: UiMessage[];
   promotion: ChatPromotionState | null;
   outgoingMessageRevision: number;
@@ -51,29 +53,36 @@ export interface ChatState {
   unlockPaywallRequest: ChatUnlockPaywallRequest | null;
 }
 
-export const initialState: ChatState = {
-  messages: [],
-  promotion: null,
-  outgoingMessageRevision: 0,
-  isReplyingAI: false,
-  pendingReplyCount: 0,
-  upgradePromptVisible: false,
-  upgradeReason: null,
-  canSendMessage: true,
-  creditBalance: 0,
-  creditsCharged: 0,
-  requiredCredits: 0,
-  shortfallCredits: 0,
-  historyLoaded: false,
-  historyTotal: 0,
-  historyLimit: 50,
-  nextHistoryOffset: 0,
-  isLoadingMoreHistory: false,
-  paymentUnlockPending: false,
-  unlockHistoryPromptVisible: false,
-  lockedHistoryCount: 0,
-  unlockHistoryError: null,
-  unlockingMessage: null,
-  unlockMessageError: null,
-  unlockPaywallRequest: null,
-};
+export function createInitialChatState(
+  characterId: string = DEFAULT_CHARACTER_ID,
+): ChatState {
+  return {
+    characterId,
+    messages: [],
+    promotion: null,
+    outgoingMessageRevision: 0,
+    isReplyingAI: false,
+    pendingReplyCount: 0,
+    upgradePromptVisible: false,
+    upgradeReason: null,
+    canSendMessage: true,
+    creditBalance: 0,
+    creditsCharged: 0,
+    requiredCredits: 0,
+    shortfallCredits: 0,
+    historyLoaded: false,
+    historyTotal: 0,
+    historyLimit: 50,
+    nextHistoryOffset: 0,
+    isLoadingMoreHistory: false,
+    paymentUnlockPending: false,
+    unlockHistoryPromptVisible: false,
+    lockedHistoryCount: 0,
+    unlockHistoryError: null,
+    unlockingMessage: null,
+    unlockMessageError: null,
+    unlockPaywallRequest: null,
+  };
+}
+
+export const initialState: ChatState = createInitialChatState();