feat(jackson): add SbxNamingStrategy for cleaner entity definitions

- Add SbxNamingStrategy to auto-map key→_KEY and meta→_META
- Entities now use @JsonNaming instead of @JsonProperty
- Update InventoryHistory and tests to use new pattern
- Update README with cleaner syntax

Before:
  @JsonProperty("_KEY") String key,
  @JsonProperty("_META") SBXMeta meta,

After:
  @JsonNaming(SbxNamingStrategy.class)
  String key,    // auto-mapped
  SBXMeta meta,  // auto-mapped

Author: HansOspina

README.md

@@ -309,11 +309,12 @@ The library provides a Spring Data-like repository pattern for type-safe, boiler
 ### Define Your Entity
 
 ```java
-@SbxModel("contact")  // Maps to SBX model name
+@SbxModel("contact")                      // Maps to SBX model name
+@JsonNaming(SbxNamingStrategy.class)      // Auto-maps key→_KEY, meta→_META
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record Contact(
-    @JsonProperty("_KEY") String key,
-    @JsonProperty("_META") SBXMeta meta,
+    String key,        // Automatically mapped to _KEY
+    SBXMeta meta,      // Automatically mapped to _META
     String name,
     String email,
     String status
@@ -403,25 +404,26 @@ contacts.query().where(...).execute();       // Full SBXFindResponse<T>
 The library uses Java records for immutable data classes:
 
 ```java
-// Simple model (without repository pattern)
+// Full repository pattern (recommended)
+@SbxModel("contact")
+@JsonNaming(SbxNamingStrategy.class)
+@JsonIgnoreProperties(ignoreUnknown = true)
 public record Contact(
-    @JsonProperty("_KEY") String key,
+    String key,
+    SBXMeta meta,
     String name,
     String email,
-    String status,
-    @JsonProperty("_META") SBXMeta meta
-) {}
+    String status
+) implements SbxEntity {}
 
-// With repository pattern
-@SbxModel("contact")
-@JsonIgnoreProperties(ignoreUnknown = true)
+// Simple model (without repository, needs @JsonProperty)
 public record Contact(
     @JsonProperty("_KEY") String key,
     @JsonProperty("_META") SBXMeta meta,
     String name,
     String email,
     String status
-) implements SbxEntity {}
+) {}
 ```
 
 ## Error Handling

src/main/java/com/sbxcloud/sbx/jackson/SbxNamingStrategy.java

@@ -0,0 +1,60 @@
+package com.sbxcloud.sbx.jackson;
+
+import com.fasterxml.jackson.databind.PropertyNamingStrategies;
+import com.fasterxml.jackson.databind.PropertyNamingStrategy;
+import com.fasterxml.jackson.databind.cfg.MapperConfig;
+import com.fasterxml.jackson.databind.introspect.AnnotatedField;
+import com.fasterxml.jackson.databind.introspect.AnnotatedMethod;
+import com.fasterxml.jackson.databind.introspect.AnnotatedParameter;
+
+/**
+ * Jackson naming strategy for SBX entities.
+ * <p>
+ * Automatically maps:
+ * <ul>
+ *   <li>{@code key} ↔ {@code _KEY}</li>
+ *   <li>{@code meta} ↔ {@code _META}</li>
+ * </ul>
+ * Other fields are left unchanged (camelCase).
+ *
+ * <pre>{@code
+ * @SbxModel("contact")
+ * @JsonNaming(SbxNamingStrategy.class)
+ * public record Contact(
+ *     String key,      // maps to _KEY
+ *     SBXMeta meta,    // maps to _META
+ *     String name,     // stays as "name"
+ *     String email     // stays as "email"
+ * ) implements SbxEntity {}
+ * }</pre>
+ */
+public class SbxNamingStrategy extends PropertyNamingStrategy {
+
+    @Override
+    public String nameForField(MapperConfig<?> config, AnnotatedField field, String defaultName) {
+        return translate(defaultName);
+    }
+
+    @Override
+    public String nameForGetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName) {
+        return translate(defaultName);
+    }
+
+    @Override
+    public String nameForSetterMethod(MapperConfig<?> config, AnnotatedMethod method, String defaultName) {
+        return translate(defaultName);
+    }
+
+    @Override
+    public String nameForConstructorParameter(MapperConfig<?> config, AnnotatedParameter ctorParam, String defaultName) {
+        return translate(defaultName);
+    }
+
+    private String translate(String name) {
+        return switch (name) {
+            case "key" -> "_KEY";
+            case "meta" -> "_META";
+            default -> name;
+        };
+    }
+}

src/test/java/com/sbxcloud/sbx/SbxModuleTest.java

@@ -1,13 +1,14 @@
 package com.sbxcloud.sbx;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.annotation.JsonProperty;
 import com.fasterxml.jackson.databind.DeserializationFeature;
 import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.annotation.JsonNaming;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 import com.sbxcloud.sbx.annotation.SbxEntity;
 import com.sbxcloud.sbx.annotation.SbxModel;
 import com.sbxcloud.sbx.jackson.SbxModule;
+import com.sbxcloud.sbx.jackson.SbxNamingStrategy;
 import com.sbxcloud.sbx.model.SBXMeta;
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.api.Test;
@@ -113,21 +114,23 @@ void shouldRoundTripCorrectly() throws Exception {
         assertEquals(original.name(), deserialized.name());
     }
 
-    // Test entities with proper @JsonProperty annotations
+    // Test entities using SbxNamingStrategy - no @JsonProperty needed!
 
     @SbxModel("test")
+    @JsonNaming(SbxNamingStrategy.class)
     @JsonIgnoreProperties(ignoreUnknown = true)
     record TestEntity(
-            @JsonProperty("_KEY") String key,
-            @JsonProperty("_META") SBXMeta meta,
+            String key,      // Auto-mapped to _KEY
+            SBXMeta meta,    // Auto-mapped to _META
             String name
     ) implements SbxEntity {}
 
     @SbxModel("test_fields")
+    @JsonNaming(SbxNamingStrategy.class)
     @JsonIgnoreProperties(ignoreUnknown = true)
     record TestEntityWithFields(
-            @JsonProperty("_KEY") String key,
-            @JsonProperty("_META") SBXMeta meta,
+            String key,
+            SBXMeta meta,
             String name,
             Integer count,
             Boolean active

src/test/java/com/sbxcloud/sbx/model/InventoryHistory.java

@@ -1,18 +1,22 @@
 package com.sbxcloud.sbx.model;
 
 import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
-import com.fasterxml.jackson.annotation.JsonProperty;
+import com.fasterxml.jackson.databind.annotation.JsonNaming;
 import com.sbxcloud.sbx.annotation.SbxEntity;
 import com.sbxcloud.sbx.annotation.SbxModel;
+import com.sbxcloud.sbx.jackson.SbxNamingStrategy;
 
 /**
  * Test model for inventory_history records in SBX domain 96.
+ * <p>
+ * Clean syntax using @JsonNaming - no @JsonProperty needed!
  */
 @SbxModel("inventory_history")
+@JsonNaming(SbxNamingStrategy.class)
 @JsonIgnoreProperties(ignoreUnknown = true)
 public record InventoryHistory(
-        @JsonProperty("_KEY") String key,
-        @JsonProperty("_META") SBXMeta meta,
+        String key,           // Auto-mapped to _KEY
+        SBXMeta meta,         // Auto-mapped to _META
         String masterlist,
         Integer week,
         Double price,