refactor(data): merge DTO models into schemas

src/app/chat/components/__tests__/chat-area-scroll.test.tsx

@@ -2,7 +2,7 @@ import { act } from "react";
 import { createRoot, type Root } from "react-dom/client";
 import { afterEach, beforeEach, describe, expect, it, vi } from "vitest";
 
-import type { UiMessage } from "@/data/dto/chat";
+import type { UiMessage } from "@/stores/chat/ui-message";
 
 import { ChatArea } from "../chat-area";
 

src/app/chat/components/chat-area.tsx

@@ -23,7 +23,7 @@ import {
 } from "react";
 import { LoaderCircle } from "lucide-react";
 
-import type { UiMessage } from "@/data/dto/chat";
+import type { UiMessage } from "@/stores/chat/ui-message";
 import { DEFAULT_CHARACTER_ID } from "@/data/constants/character";
 import { usePullToRefresh } from "@/hooks/use-pull-to-refresh";