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/View/Tree/NodeContent/Reverter/CategoryReverter.spec.ts

@@ -8,15 +8,15 @@ import { UserSelectionStub } from '@tests/unit/shared/Stubs/UserSelectionStub';
 import { SelectedScriptStub } from '@tests/unit/shared/Stubs/SelectedScriptStub';
 import type { SelectedScript } from '@/application/Context/State/Selection/Script/SelectedScript';
 import { CategorySelectionStub } from '@tests/unit/shared/Stubs/CategorySelectionStub';
-import type { IScript } from '@/domain/IScript';
+import type { Script } from '@/domain/Executables/Script/Script';
 
 describe('CategoryReverter', () => {
   describe('getState', () => {
     // arrange
     const testScenarios: ReadonlyArray<{
       readonly description: string;
-      readonly allScripts: readonly IScript[];
-      readonly selectScripts: (allScripts: readonly IScript[]) => readonly SelectedScript[];
+      readonly allScripts: readonly Script[];
+      readonly selectScripts: (allScripts: readonly Script[]) => readonly SelectedScript[];
       readonly expectedState: boolean;
     }> = [
       {