add common module

user-service/build.gradle

@@ -0,0 +1,10 @@
+dependencies {
+    // BCrypt for password hashing
+    implementation 'org.springframework.security:spring-security-crypto'
+
+    // Redis for session management
+    implementation 'org.springframework.boot:spring-boot-starter-data-redis'
+
+    // OpenFeign for external API calls (사업자번호 검증)
+    implementation 'org.springframework.cloud:spring-cloud-starter-openfeign'
+}