fix: support @PostConstruct methods in parent classes

Recursively scan parent class hierarchy to collect all @PostConstruct
methods, ensuring parent methods are executed before child methods.

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

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

@@ -254,14 +254,21 @@ public class BeanScanner {
 
 	private List<Method> findPostConstructs(Class<?> clazz) {
 		List<Method> methods = new ArrayList<>();
-		for (Method method : clazz.getDeclaredMethods()) {
+		Class<?> currentClass = clazz;
+
+		// 从当前类向上遍历到 Object，收集所有 @PostConstruct 方法
+		while (currentClass != null && currentClass != Object.class) {
+			for (Method method : currentClass.getDeclaredMethods()) {
 				if (method.isAnnotationPresent(PostConstruct.class)) {
 					if (method.getParameterCount() != 0) {
 						throw new InjectException("@PostConstruct method must have no parameters: %s".formatted(method.getName()));
 					}
-				methods.add(method);
+					// 添加到列表头部，确保父类方法先执行
+					methods.addFirst(method);
 				}
 			}
+			currentClass = currentClass.getSuperclass();
+		}
 		return methods;
 	}
 }