refactor(infra): remove unused construct variable assignments

Author: Yuriy Bezsonov

infra/cdk/src/main/java/sample/com/WorkshopStack.java

@@ -96,13 +96,13 @@ public WorkshopStack(final Construct scope, final String id, final StackProps pr
                     .build());
 
             // ECR Registry settings (Repository Creation Template for create-on-push)
-            EcrRegistry ecrRegistry = new EcrRegistry(this, "EcrRegistry",
+            new EcrRegistry(this, "EcrRegistry",
                 EcrRegistry.EcrRegistryProps.builder()
                     .prefix(prefix)
                     .build());
 
             // Thread Analysis (thread dump Lambda + API Gateway)
-            ThreadAnalysis threadAnalysis = new ThreadAnalysis(this, "ThreadAnalysis",
+            new ThreadAnalysis(this, "ThreadAnalysis",
                 ThreadAnalysis.ThreadAnalysisProps.builder()
                     .prefix(prefix)
                     .vpc(vpc.getVpc())
@@ -112,13 +112,13 @@ public WorkshopStack(final Construct scope, final String id, final StackProps pr
                     .build());
 
             // AI JVM Analyzer (Pod Identity role for ai-jvm-analyzer)
-            AiJvmAnalyzer aiJvmAnalyzer = new AiJvmAnalyzer(this, "AiJvmAnalyzer",
+            new AiJvmAnalyzer(this, "AiJvmAnalyzer",
                 AiJvmAnalyzer.AiJvmAnalyzerProps.builder()
                     .workshopBucket(workshopBucket.getBucket())
                     .build());
 
             // Unicorn construct: Roles + DB Setup (uses unicorn* naming for workshop content compatibility)
-            Unicorn unicorn = new Unicorn(this, "Unicorn", Unicorn.UnicornProps.builder()
+            new Unicorn(this, "Unicorn", Unicorn.UnicornProps.builder()
                 .vpc(vpc.getVpc())
                 .database(database)
                 .workshopBucket(workshopBucket.getBucket())

infra/cdk/src/main/java/sample/com/constructs/CodeBuild.java

@@ -12,7 +12,6 @@
 import software.amazon.awscdk.services.ec2.SubnetType;
 import software.constructs.Construct;
 
-import java.security.MessageDigest;
 import java.util.Map;
 import java.util.List;
 import java.util.Arrays;