feat: add SBXRecord interface for typed entities

Author: HansOspina

src/main/java/com/sbxcloud/sbx/model/SBXRecord.java

@@ -0,0 +1,62 @@
+package com.sbxcloud.sbx.model;
+
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+/**
+ * Base interface for SBX record types.
+ * <p>
+ * All SBX records have a {@code _KEY} (primary key) and optional {@code _META} (metadata).
+ *
+ * <h2>Usage with Java Records</h2>
+ * <pre>{@code
+ * @JsonIgnoreProperties(ignoreUnknown = true)
+ * public record Contact(
+ *     @JsonProperty("_KEY") String key,
+ *     @JsonProperty("_META") SBXMeta meta,
+ *     String name,
+ *     String email,
+ *     String status
+ * ) implements SBXRecord {}
+ * }</pre>
+ *
+ * <h2>Creating New Records</h2>
+ * <pre>{@code
+ * // For inserts, key and meta are null
+ * var newContact = new Contact(null, null, "John", "john@example.com", "ACTIVE");
+ *
+ * // Or add a convenience constructor
+ * public record Contact(...) implements SBXRecord {
+ *     public Contact(String name, String email, String status) {
+ *         this(null, null, name, email, status);
+ *     }
+ * }
+ * }</pre>
+ *
+ * <h2>Accessing Metadata</h2>
+ * <pre>{@code
+ * Contact contact = response.results().get(0);
+ * System.out.println("Key: " + contact.key());
+ * if (contact.meta() != null) {
+ *     System.out.println("Created: " + contact.meta().createdTime());
+ *     System.out.println("Updated: " + contact.meta().updateTime());
+ * }
+ * }</pre>
+ *
+ * @see SBXMeta
+ */
+public interface SBXRecord {
+
+    /**
+     * The unique key for this record ({@code _KEY} in JSON).
+     */
+    @JsonProperty("_KEY")
+    String key();
+
+    /**
+     * The metadata for this record ({@code _META} in JSON).
+     * Contains createdTime, updateTime, modelId, modelName, domain.
+     */
+    @JsonProperty("_META")
+    SBXMeta meta();
+}