chore: acquire-core migration monorepo (legacy C + Spring Boot target skeleton)

TxCore/ECPG legacy 매입·정산 C 슬라이스(빌드검증) + Spring Boot 멀티모듈 골격(mvn test green) + MIGRATION.md 전환룰 + CI(boot 빌드).

boot/pom.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.3.5</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.klaro.acquirecore</groupId>
+    <artifactId>acquire-core-boot</artifactId>
+    <version>0.0.1-SNAPSHOT</version>
+    <packaging>pom</packaging>
+    <name>acquire-core-boot</name>
+    <description>Spring Boot 전환 타겟: TxCore 공통 프레임워크 + 매입 업무 모듈</description>
+
+    <properties>
+        <java.version>17</java.version>
+        <maven.compiler.release>17</maven.compiler.release>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
+
+    <modules>
+        <module>common-framework</module>
+        <module>modules/acquiring</module>
+    </modules>
+
+    <dependencyManagement>
+        <dependencies>
+            <!-- 내부 모듈: common-framework 를 업무 모듈이 참조 -->
+            <dependency>
+                <groupId>com.klaro.acquirecore</groupId>
+                <artifactId>common-framework</artifactId>
+                <version>${project.version}</version>
+            </dependency>
+        </dependencies>
+    </dependencyManagement>
+
+</project>