fix: run gradle natively in runner to avoid isolated mount issue

.gitea/workflows/deploy.yml

@@ -12,13 +12,13 @@ jobs:
     runs-on: ubuntu-latest
     steps:
 
-      - name: Prepare Environment (Install Node.js & Git)
+      - name: Prepare Environment (Install Node.js & Git & Java 21)
         run: |
           if command -v apt-get &> /dev/null; then
             apt-get update
-            apt-get install -y nodejs git
+            apt-get install -y nodejs git openjdk-21-jdk
           elif command -v apk &> /dev/null; then
-            apk add --no-cache nodejs git
+            apk add --no-cache nodejs git openjdk21
           fi
 
       - name: Checkout Code
@@ -33,14 +33,10 @@ jobs:
         run: |
           echo "Starting Standard CI/CD Deploy pipeline..."
           
-          # 1. gradle 공식 이미지로 바로 컴파일 빌드!
-          docker run --rm \
-            -v /app:/app \
-            -v /var/run/docker.sock:/var/run/docker.sock \
-            -v /home/ubuntu/.gradle:/home/gradle/.gradle \
-            -w /app \
-            gradle:8-jdk21 \
-            ./gradlew bootJar -x test
+          # 1. runner에 설치된 java로 직접 빌드! (격리된 환경 문제 해결)
+          cd /app
+          chmod +x gradlew
+          ./gradlew bootJar -x test
           
           # 2. 빌드 결과 plain jar 아카이브 정리
           find /app -name "*-plain.jar" -delete