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.

src/application/Context/State/Code/Event/ICodeChangedEvent.ts

@@ -1,11 +1,11 @@
-import type { IScript } from '@/domain/IScript';
+import type { Script } from '@/domain/Executables/Script/Script';
 import type { ICodePosition } from '@/application/Context/State/Code/Position/ICodePosition';
 
 export interface ICodeChangedEvent {
   readonly code: string;
-  readonly addedScripts: ReadonlyArray<IScript>;
-  readonly removedScripts: ReadonlyArray<IScript>;
-  readonly changedScripts: ReadonlyArray<IScript>;
+  readonly addedScripts: ReadonlyArray<Script>;
+  readonly removedScripts: ReadonlyArray<Script>;
+  readonly changedScripts: ReadonlyArray<Script>;
   isEmpty(): boolean;
-  getScriptPositionInCode(script: IScript): ICodePosition;
+  getScriptPositionInCode(script: Script): ICodePosition;
 }