STT 테스트 환경 구성 및 유저스토리 업데이트

- docker-compose.test.yml 추가: 테스트용 컨테이너 환경 구성
- STT 테스트 설정 및 컨트롤러 테스트 코드 추가
- application.yml 업데이트
- 테스트 스크립트 추가
- 유저스토리 문서 업데이트

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

stt/src/main/resources/application.yml

@@ -4,9 +4,9 @@ spring:
 
   # Database Configuration
   datasource:
-    url: jdbc:${DB_KIND:postgresql}://${DB_HOST:4.230.65.89}:${DB_PORT:5432}/${DB_NAME:sttdb}
-    username: ${DB_USERNAME:hgzerouser}
-    password: ${DB_PASSWORD:Hi5Jessica!}
+    url: jdbc:${DB_KIND:postgresql}://${DB_HOST:localhost}:${DB_PORT:5432}/${DB_NAME:sttdb}
+    username: ${DB_USERNAME:stt_user}
+    password: ${DB_PASSWORD:}
     driver-class-name: org.postgresql.Driver
     hikari:
       maximum-pool-size: 20
@@ -30,9 +30,9 @@ spring:
   # Redis Configuration
   data:
     redis:
-      host: ${REDIS_HOST:20.249.177.114}
+      host: ${REDIS_HOST:localhost}
       port: ${REDIS_PORT:6379}
-      password: ${REDIS_PASSWORD:Hi5Jessica!}
+      password: ${REDIS_PASSWORD:}
       timeout: 2000ms
       lettuce:
         pool:
@@ -40,7 +40,7 @@ spring:
           max-idle: 8
           min-idle: 0
           max-wait: -1ms
-      database: ${REDIS_DATABASE:2}
+      database: ${REDIS_DATABASE:3}
 
 # Server Configuration
 server:
@@ -48,9 +48,9 @@ server:
 
 # JWT Configuration
 jwt:
-  secret: ${JWT_SECRET:}
-  access-token-validity: ${JWT_ACCESS_TOKEN_VALIDITY:3600}
-  refresh-token-validity: ${JWT_REFRESH_TOKEN_VALIDITY:604800}
+  secret: ${JWT_SECRET:HGZero_Secret_Key_For_Development_Only}
+  access-token-validity: ${JWT_ACCESS_TOKEN_VALIDITY:1800}
+  refresh-token-validity: ${JWT_REFRESH_TOKEN_VALIDITY:86400}
 
 # CORS Configuration
 cors: