chore: remove legacy Groovy Gradle files and relocated converter

build.gradle and settings.gradle superseded by build.gradle.kts
and settings.gradle.kts. FirearmTypeConverter moved to
domain/converter/ package.

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

build.gradle

@@ -1,37 +0,0 @@
-plugins {
-    id 'java'
-    id 'org.springframework.boot' version '3.5.13'
-    id 'io.spring.dependency-management' version '1.1.7'
-}
-
-group = 'com.onixbyte'
-version = '0.0.1-SNAPSHOT'
-description = 'delta-force-guide-server'
-
-java {
-    toolchain {
-        languageVersion = JavaLanguageVersion.of(21)
-    }
-}
-
-repositories {
-    mavenCentral()
-}
-
-dependencies {
-    implementation 'org.springframework.boot:spring-boot-starter-cache'
-    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
-    implementation 'org.springframework.boot:spring-boot-starter-data-redis'
-    implementation 'org.springframework.boot:spring-boot-starter-security'
-    implementation 'org.springframework.boot:spring-boot-starter-validation'
-    implementation 'org.springframework.boot:spring-boot-starter-web'
-    implementation 'org.springdoc:springdoc-openapi-starter-webmvc-ui:2.8.16'
-    runtimeOnly 'org.postgresql:postgresql'
-    testImplementation 'org.springframework.boot:spring-boot-starter-test'
-    testImplementation 'org.springframework.security:spring-security-test'
-    testRuntimeOnly 'org.junit.platform:junit-platform-launcher'
-}
-
-tasks.named('test') {
-    useJUnitPlatform()
-}

settings.gradle

@@ -1 +0,0 @@
-rootProject.name = 'delta-force-guide-server'

src/main/java/com/onixbyte/deltaforceguide/domain/entity/FirearmTypeConverter.java

@@ -1,20 +0,0 @@
-package com.onixbyte.deltaforceguide.domain.entity;
-
-import com.onixbyte.deltaforceguide.enumeration.FirearmType;
-import jakarta.persistence.AttributeConverter;
-import jakarta.persistence.Converter;
-
-@Converter(autoApply = false)
-public class FirearmTypeConverter implements AttributeConverter<FirearmType, Integer> {
-
-    @Override
-    public Integer convertToDatabaseColumn(FirearmType attribute) {
-        return attribute == null ? null : attribute.getCode();
-    }
-
-    @Override
-    public FirearmType convertToEntityAttribute(Integer dbData) {
-        return FirearmType.fromCode(dbData);
-    }
-}
-