Fix Dockerfile paths and add main to ValidationRunner

dat-was-lib/src/main/java/io/shinhanlife/dat/lib/validation/McpToolNameValidationRunner.java

@@ -11,4 +11,11 @@ public final class McpToolNameValidationRunner {
     static void validate(Path projectRoot) {
         McpToolNameValidator.assertUnique(projectRoot);
     }
+
+    public static void main(String[] args) {
+        if (args.length == 0) {
+            throw new IllegalArgumentException("Project root path must be provided");
+        }
+        validate(Path.of(args[0]));
+    }
 }