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/application/Parser/ScriptingDefinition/CodeSubstituter.spec.ts

@@ -1,6 +1,6 @@
 import { describe, it, expect } from 'vitest';
 import { CodeSubstituter } from '@/application/Parser/ScriptingDefinition/CodeSubstituter';
-import type { IExpressionsCompiler } from '@/application/Parser/Script/Compiler/Expressions/IExpressionsCompiler';
+import type { IExpressionsCompiler } from '@/application/Parser/Executable/Script/Compiler/Expressions/IExpressionsCompiler';
 import { ProjectDetailsStub } from '@tests/unit/shared/Stubs/ProjectDetailsStub';
 import { ExpressionsCompilerStub } from '@tests/unit/shared/Stubs/ExpressionsCompilerStub';
 import { itEachAbsentStringValue } from '@tests/unit/shared/TestCases/AbsentTests';