Update GitHub workflows to use JDK 21 (Oracle)

All workflows now use JDK 21 with the Oracle distribution instead of JDK 17 or 11 with Temurin. This ensures consistency and leverages the latest Java features and security updates.

.github/workflows/codeql.yml

@@ -28,8 +28,8 @@ jobs:
         if: matrix.language == 'java'
         uses: actions/setup-java@v5
         with:
-          distribution: temurin
-          java-version: '11'
+          distribution: oracle
+          java-version: '21'
 
       - name: Initialize CodeQL
         uses: github/codeql-action/init@v3