优化目录结构

backend/src/main/java/com/openisle/model/User.java

@@ -0,0 +1,64 @@
+package com.openisle.model;
+
+import jakarta.persistence.*;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+import lombok.Setter;
+import org.hibernate.annotations.CreationTimestamp;
+import java.time.LocalDateTime;
+
+import com.openisle.model.Role;
+
+/**
+ * Simple user entity with basic fields and a role.
+ */
+
+@Entity
+@Getter
+@Setter
+@NoArgsConstructor
+@Table(name = "users")
+public class User {
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(nullable = false, unique = true)
+    private String username;
+
+    @Column(nullable = false, unique = true)
+    private String email;
+
+    @Column(nullable = false)
+    private String password;
+
+    @Column(nullable = false)
+    private boolean verified = false;
+
+    private String verificationCode;
+
+    private String passwordResetCode;
+
+    private String avatar;
+
+    @Column(nullable = false)
+    private int experience = 0;
+
+    @Column(length = 1000)
+    private String introduction;
+
+    @Column(length = 1000)
+    private String registerReason;
+
+    @Column(nullable = false)
+    private boolean approved = true;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private Role role = Role.USER;
+
+    @CreationTimestamp
+    @Column(nullable = false, updatable = false,
+            columnDefinition = "DATETIME(6) DEFAULT CURRENT_TIMESTAMP(6)")
+    private LocalDateTime createdAt;
+}