refactor(models): migrate 28 data models to Zod schema-driven pattern

src/data/models/chat/sync_message.ts

@@ -2,40 +2,37 @@
  * 待同步的单条消息
  * 原始 Dart: SyncMessage (lib/data/models/chat/chat_sync.dart)
  */
-export class SyncMessage {
-  readonly role: string;
-  readonly content: string;
-  readonly timestamp: string;
+import { z } from "zod";
 
-  constructor(params: { role: string; content: string; timestamp: string }) {
-    this.role = params.role;
-    this.content = params.content;
-    this.timestamp = params.timestamp;
+export const SyncMessageSchema = z.object({
+  role: z.string(),
+  content: z.string(),
+  timestamp: z.string(),
+});
+
+export type SyncMessageInput = z.input<typeof SyncMessageSchema>;
+export type SyncMessageData = z.output<typeof SyncMessageSchema>;
+
+export class SyncMessage {
+  declare readonly role: string;
+  declare readonly content: string;
+  declare readonly timestamp: string;
+
+  private constructor(input: SyncMessageInput) {
+    const data = SyncMessageSchema.parse(input);
+    Object.assign(this, data);
     Object.freeze(this);
   }
 
-  toJson(): Record<string, unknown> {
-    return {
-      role: this.role,
-      content: this.content,
-      timestamp: this.timestamp,
-    };
+  static from(input: SyncMessageInput): SyncMessage {
+    return new SyncMessage(input);
   }
 
-  static fromJson(json: Record<string, unknown>): SyncMessage {
-    const requireString = (key: string): string => {
-      const v = json[key];
-      if (typeof v !== "string") {
-        throw new Error(
-          `SyncMessage.${key} is required and must be a string`
-        );
-      }
-      return v;
-    };
-    return new SyncMessage({
-      role: requireString("role"),
-      content: requireString("content"),
-      timestamp: requireString("timestamp"),
-    });
+  static fromJson(json: unknown): SyncMessage {
+    return SyncMessage.from(json as SyncMessageInput);
+  }
+
+  toJson(): SyncMessageData {
+    return SyncMessageSchema.parse(this);
   }
 }