Refactor to unify scripts/categories as Executable

This commit consolidates scripts and categories under a unified
'Executable' concept. This simplifies the architecture and improves code
readability.

- Introduce subfolders within `src/domain` to segregate domain elements.
- Update class and interface names by removing the 'I' prefix in
  alignment with new coding standards.
- Replace 'Node' with 'Executable' to clarify usage; reserve 'Node'
  exclusively for the UI's tree component.

tests/unit/presentation/components/Scripts/Menu/Recommendation/RecommendationStatusTestScenario.ts

@@ -1,5 +1,5 @@
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
-import { RecommendationLevel } from '@/domain/RecommendationLevel';
+import { RecommendationLevel } from '@/domain/Executables/Script/RecommendationLevel';
 import { CategoryCollectionStateStub } from '@tests/unit/shared/Stubs/CategoryCollectionStateStub';
 import { ScriptSelectionStub } from '@tests/unit/shared/Stubs/ScriptSelectionStub';
 import { ScriptStub } from '@tests/unit/shared/Stubs/ScriptStub';