Add event dispatching to manifest compilation

This update introduces event dispatching in the manifest compilation process. PreManifestCompileEvent and PostManifestCompileEvent have been added, which are dispatched before and after the compilation respectively. The modification enhances the flexibility and extensibility of the manifest compilation process by allowing custom actions just before or after compilation.

src/Event/NullEventDispatcher.php

@@ -8,8 +8,8 @@
 
 final readonly class NullEventDispatcher implements EventDispatcherInterface
 {
-    public function dispatch(object $event): void
+    public function dispatch(object $event): object
     {
-        // Do nothing
+        return $event;
     }
 }