feat: add Card entity and CardStatus enum

src/main/java/com/example/bankcards/entity/Card.java

@@ -0,0 +1,75 @@
+package com.example.bankcards.entity;
+
+@Entity
+@Table(name = "cards")
+public class Card {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "card_number_encrypted", nullable = false)
+    private String cardNumberEncrypted;
+
+    @ManyToOne(fetch = FetchType.LAZY)
+    @JoinColumn(name = "owner_id", nullable = false)
+    private User owner;
+
+    @Column(name = "expiry_date", nullable = false)
+    private LocalDate expiryDate;
+
+    @Enumerated(EnumType.STRING)
+    @Column(nullable = false)
+    private CardStatus status;
+
+    @Column(nullable = false, precision = 19, scale = 2)
+    private BigDecimal balance;
+
+    public Long getId() {
+        return id;
+    }
+
+    public void setId(Long id) {
+        this.id = id;
+    }
+
+    public String getCardNumberEncrypted() {
+        return cardNumberEncrypted;
+    }
+
+    public void setCardNumberEncrypted(String cardNumberEncrypted) {
+        this.cardNumberEncrypted = cardNumberEncrypted;
+    }
+
+    public User getOwner() {
+        return owner;
+    }
+
+    public void setOwner(User owner) {
+        this.owner = owner;
+    }
+
+    public LocalDate getExpiryDate() {
+        return expiryDate;
+    }
+
+    public void setExpiryDate(LocalDate expiryDate) {
+        this.expiryDate = expiryDate;
+    }
+
+    public CardStatus getStatus() {
+        return status;
+    }
+
+    public void setStatus(CardStatus status) {
+        this.status = status;
+    }
+
+    public BigDecimal getBalance() {
+        return balance;
+    }
+
+    public void setBalance(BigDecimal balance) {
+        this.balance = balance;
+    }
+}

src/main/java/com/example/bankcards/entity/CardStatus.java

@@ -0,0 +1,5 @@
+package com.example.bankcards.entity;
+
+public enum CardStatus {
+    ACTIVE, BLOCKED, EXPIRED
+}