feat(di): add proactive initializer finder for interface resolution

- Add ProactiveInitializerFinder to search for initializers when not found in registry
- Add InitializerInfo value object to store initializer metadata
- Implement multi-step search strategy: DefaultImplementation, naming convention, directory, subdirectories, module
- Integrate proactive finder into DefaultContainer for better interface resolution
- Simplify AppBootstrapper by moving initialization logic to DefaultContainer
- Improve error messages in ClassNotInstantiable with proactive finder context

src/Framework/Discovery/InitializerProcessor.php

@@ -48,7 +48,7 @@ final readonly class InitializerProcessor
         $logger->debug("InitializerProcessor: Processing " . count($initializerResults) . " initializers");
 
         $dependencyGraph = new InitializerDependencyGraph($this->reflectionProvider);
-        /** @var FailedInitializer[] */
+        /** @var FailedInitializer[] $failedInitializers */
         $failedInitializers = [];
 
         // Phase 1: Setup-Initializer sofort ausführen & Service-Initializer zum Graph hinzufügen