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/Parser/Executable/Script/Compiler/Function/SharedFunction.ts

@@ -0,0 +1,62 @@
+import {
+  FunctionBodyType, type IFunctionCode, type ISharedFunction, type SharedFunctionBody,
+} from './ISharedFunction';
+import type { FunctionCall } from './Call/FunctionCall';
+import type { IReadOnlyFunctionParameterCollection } from './Parameter/IFunctionParameterCollection';
+
+export function createCallerFunction(
+  name: string,
+  parameters: IReadOnlyFunctionParameterCollection,
+  callSequence: readonly FunctionCall[],
+): ISharedFunction {
+  if (!callSequence.length) {
+    throw new Error(`missing call sequence in function "${name}"`);
+  }
+  return new SharedFunction(name, parameters, callSequence, FunctionBodyType.Calls);
+}
+
+export function createFunctionWithInlineCode(
+  name: string,
+  parameters: IReadOnlyFunctionParameterCollection,
+  code: string,
+  revertCode?: string,
+): ISharedFunction {
+  if (!code) {
+    throw new Error(`undefined code in function "${name}"`);
+  }
+  const content: IFunctionCode = {
+    execute: code,
+    revert: revertCode,
+  };
+  return new SharedFunction(name, parameters, content, FunctionBodyType.Code);
+}
+
+class SharedFunction implements ISharedFunction {
+  public readonly body: SharedFunctionBody;
+
+  constructor(
+    public readonly name: string,
+    public readonly parameters: IReadOnlyFunctionParameterCollection,
+    content: IFunctionCode | readonly FunctionCall[],
+    bodyType: FunctionBodyType,
+  ) {
+    if (!name) { throw new Error('missing function name'); }
+
+    switch (bodyType) {
+      case FunctionBodyType.Code:
+        this.body = {
+          type: FunctionBodyType.Code,
+          code: content as IFunctionCode,
+        };
+        break;
+      case FunctionBodyType.Calls:
+        this.body = {
+          type: FunctionBodyType.Calls,
+          calls: content as readonly FunctionCall[],
+        };
+        break;
+      default:
+        throw new Error(`unknown body type: ${FunctionBodyType[bodyType]}`);
+    }
+  }
+}