Improve `DelegateActionManager` error handling for invalid handlers

- Add validation to ensure classes annotated with `@Action` implement `ActionHandler`, throwing `IllegalArgumentException` for mismatches.
- Fix minor formatting issue in `@Action` annotation for `GetGenreByIdHandler`.

src/main/java/com/mediamanager/service/delegate/DelegateActionManager.java

@@ -66,14 +66,17 @@ public class DelegateActionManager {
 
     @SuppressWarnings("unchecked")
     private ActionHandler instantiateHandler(Class<?> clazz) throws Exception {
+        if(!ActionHandler.class.isAssignableFrom(clazz)){
+            throw new IllegalArgumentException(
+                    clazz.getName() + " is annotated with @Action but does not implement ActionHandler");
+
+        }
         logger.debug("Attempting to instantiate handler: {}", clazz.getSimpleName());
 
 
         Constructor<?>[] constructors = clazz.getDeclaredConstructors();
 
 
-        Constructor<?>[] constructors = clazz.getDeclaredConstructors();
-
         // Sort constructors by parameter count (descending) to prefer DI constructors
         java.util.Arrays.sort(constructors, (c1, c2) -> 
             Integer.compare(c2.getParameterCount(), c1.getParameterCount()));

src/main/java/com/mediamanager/service/delegate/handler/genre/GetGenreByIdHandler.java

@@ -14,7 +14,7 @@ import org.apache.logging.log4j.Logger;
 
 import java.util.Optional;
 
-@Action( "genre.getById")
+@Action("genre.getById")
 public class GetGenreByIdHandler implements ActionHandler {
     private static final Logger logger = LogManager.getLogger(GetGenreByIdHandler.class);