feat: add field injection after constructor injection

Enable @Inject field injection in the bean creation lifecycle. Fields are now injected after constructor injection and before PostConstruct invocation, allowing beans to use both constructor and field injection simultaneously.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

src/main/java/com/imyeyu/inject/BeanFactory.java

@@ -112,6 +112,8 @@ public class BeanFactory {
 			} else {
 				instance = createBeanFromConstructor(definition);
 			}
+			// 在构造器注入后执行字段注入
+			injectFields(instance);
 			if (definition.getScope() == ScopeType.SINGLETON) {
 				context.setSingleton(name, instance);
 			}