Improve security by isolating code execution more

This commit enhances application security against potential attacks by
isolating dependencies that access the host system (like file
operations) from the renderer process. It narrows the exposed
functionality to script execution only, adding an extra security layer.

The changes allow secure and scalable API exposure, preparing for future
functionalities such as desktop notifications for script errors (#264),
improved script execution handling (#296), and creating restore points
(#50) in a secure and repeatable way.

Changes include:

- Inject `CodeRunner` into Vue components via dependency injection.
- Move `CodeRunner` to the application layer as an abstraction for
  better domain-driven design alignment.
- Refactor `SystemOperations` and related interfaces, removing the `I`
  prefix.
- Update architecture documentation for clarity.
- Update return types in `NodeSystemOperations` to match the Node APIs.
- Improve `WindowVariablesProvider` integration tests for better error
  context.
- Centralize type checks with common functions like `isArray` and
  `isNumber`.
- Change `CodeRunner` to use `os` parameter, ensuring correct window
  variable injection.
- Streamline API exposure to the renderer process:
  - Automatically bind function contexts to prevent loss of original
    context.
  - Implement a way to create facades (wrapper/proxy objects) for
    increased security.

src/infrastructure/WindowVariables/WindowVariablesValidator.ts

@@ -1,12 +1,14 @@
 import { OperatingSystem } from '@/domain/OperatingSystem';
-import { PropertyKeys } from '@/TypeHelpers';
+import {
+  PropertyKeys, isBoolean, isFunction, isNumber, isPlainObject,
+} from '@/TypeHelpers';
 import { WindowVariables } from './WindowVariables';
 
 /**
  * Checks for consistency in runtime environment properties injected by Electron preloader.
  */
 export function validateWindowVariables(variables: Partial<WindowVariables>) {
-  if (!isObject(variables)) {
+  if (!isPlainObject(variables)) {
     throw new Error('window is not an object');
   }
   const errors = [...testEveryProperty(variables)];
@@ -21,7 +23,7 @@ function* testEveryProperty(variables: Partial<WindowVariables>): Iterable<strin
   } = {
     os: testOperatingSystem(variables.os),
     isDesktop: testIsDesktop(variables.isDesktop),
-    system: testSystem(variables),
+    codeRunner: testCodeRunner(variables),
     log: testLogger(variables),
   };
 
@@ -49,14 +51,15 @@ function testLogger(variables: Partial<WindowVariables>): boolean {
   if (!variables.isDesktop) {
     return true;
   }
-  return isObject(variables.log);
+  return isPlainObject(variables.log);
 }
 
-function testSystem(variables: Partial<WindowVariables>): boolean {
+function testCodeRunner(variables: Partial<WindowVariables>): boolean {
   if (!variables.isDesktop) {
     return true;
   }
-  return isObject(variables.system);
+  return isPlainObject(variables.codeRunner)
+    && isFunction(variables.codeRunner.runCode);
 }
 
 function testIsDesktop(isDesktop: unknown): boolean {
@@ -65,17 +68,3 @@ function testIsDesktop(isDesktop: unknown): boolean {
   }
   return isBoolean(isDesktop);
 }
-
-function isNumber(variable: unknown): variable is number {
-  return typeof variable === 'number';
-}
-
-function isBoolean(variable: unknown): variable is boolean {
-  return typeof variable === 'boolean';
-}
-
-function isObject(variable: unknown): variable is object {
-  return Boolean(variable) // the data type of null is an object
-    && typeof variable === 'object'
-    && !Array.isArray(variable);
-}