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

src/data/models/user/recent_memory.ts

@@ -1,59 +1,39 @@
 /**
  * 最近记忆模型
  * 原始 Dart: RecentMemory (lib/data/models/user/recent_memory.dart)
- *
- * 注：原始 Dart 中 `createdAt` 为 `String?`，按"全部非空"约定兜底为空串。
  */
-export class RecentMemory {
-  readonly type: string;
-  readonly content: string;
-  readonly importance: number;
-  readonly createdAt: string;
+import { z } from "zod";
 
-  constructor(params: {
-    type: string;
-    content: string;
-    importance: number;
-    createdAt?: string;
-  }) {
-    this.type = params.type;
-    this.content = params.content;
-    this.importance = params.importance;
-    this.createdAt = params.createdAt ?? "";
+export const RecentMemorySchema = z.object({
+  type: z.string(),
+  content: z.string(),
+  importance: z.number(),
+  createdAt: z.string().default(""),
+});
+
+export type RecentMemoryInput = z.input<typeof RecentMemorySchema>;
+export type RecentMemoryData = z.output<typeof RecentMemorySchema>;
+
+export class RecentMemory {
+  declare readonly type: string;
+  declare readonly content: string;
+  declare readonly importance: number;
+  declare readonly createdAt: string;
+
+  private constructor(data: RecentMemoryData) {
+    Object.assign(this, data);
     Object.freeze(this);
   }
 
-  toJson(): Record<string, unknown> {
-    return {
-      type: this.type,
-      content: this.content,
-      importance: this.importance,
-      createdAt: this.createdAt,
-    };
+  static from(input: RecentMemoryInput): RecentMemory {
+    return new RecentMemory(RecentMemorySchema.parse(input));
   }
 
-  static fromJson(json: Record<string, unknown>): RecentMemory {
-    const requireString = (key: string): string => {
-      const v = json[key];
-      if (typeof v !== "string") {
-        throw new Error(
-          `RecentMemory.${key} is required and must be a string`
-        );
-      }
-      return v;
-    };
-    const importance = json.importance;
-    if (typeof importance !== "number") {
-      throw new Error(
-        "RecentMemory.importance is required and must be a number"
-      );
-    }
-    return new RecentMemory({
-      type: requireString("type"),
-      content: requireString("content"),
-      importance,
-      createdAt:
-        typeof json.createdAt === "string" ? json.createdAt : undefined,
-    });
+  static fromJson(json: unknown): RecentMemory {
+    return RecentMemory.from(json as RecentMemoryInput);
+  }
+
+  toJson(): RecentMemoryData {
+    return RecentMemorySchema.parse(this);
   }
 }