feat(chat-character-image): 캐릭터 이미지

- 등록, 리스트, 상세, 트리거 단어 업데이트, 삭제 기능 추가

src/main/kotlin/kr/co/vividnext/sodalive/aws/cloudfront/ImageContentCloudFront.kt

@@ -0,0 +1,48 @@
+package kr.co.vividnext.sodalive.aws.cloudfront
+
+import com.amazonaws.services.cloudfront.CloudFrontUrlSigner
+import org.springframework.beans.factory.annotation.Value
+import org.springframework.stereotype.Component
+import java.nio.file.Files
+import java.nio.file.Paths
+import java.security.KeyFactory
+import java.security.PrivateKey
+import java.security.spec.PKCS8EncodedKeySpec
+import java.util.Date
+
+/**
+ * 이미지(CloudFront) 서명 URL 생성기
+ * - cloud.aws.cloud-front.* 설정을 사용
+ */
+@Component
+class ImageContentCloudFront(
+    @Value("\${cloud.aws.cloud-front.host}")
+    private val cloudfrontDomain: String,
+
+    @Value("\${cloud.aws.cloud-front.private-key-file-path}")
+    private val privateKeyFilePath: String,
+
+    @Value("\${cloud.aws.cloud-front.key-pair-id}")
+    private val keyPairId: String
+) {
+    fun generateSignedURL(
+        resourcePath: String,
+        expirationTimeMillis: Long
+    ): String {
+        val privateKey = loadPrivateKey(privateKeyFilePath)
+        return CloudFrontUrlSigner.getSignedURLWithCannedPolicy(
+            "$cloudfrontDomain/$resourcePath",
+            keyPairId,
+            privateKey,
+            Date(System.currentTimeMillis() + expirationTimeMillis)
+        )
+    }
+
+    private fun loadPrivateKey(resourceName: String): PrivateKey {
+        val path = Paths.get(resourceName)
+        val bytes = Files.readAllBytes(path)
+        val keySpec = PKCS8EncodedKeySpec(bytes)
+        val keyFactory = KeyFactory.getInstance("RSA")
+        return keyFactory.generatePrivate(keySpec)
+    }
+}