Fix code highlighting and optimize category select

This commit introduces a batched debounce mechanism for managing user
selection state changes. It effectively reduces unnecessary processing
during rapid script checking, preventing multiple triggers for code
compilation and UI rendering.

Key improvements include:

- Enhanced performance, especially noticeable when selecting large
  categories. This update resolves minor UI freezes experienced when
  selecting categories with numerous scripts.
- Correction of a bug where the code area only highlighted the last
  selected script when multiple scripts were chosen.

Other changes include:

- Timing functions:
  - Create a `Timing` folder for `throttle` and the new
    `batchedDebounce` functions.
  - Move these functions to the application layer from the presentation
    layer, reflecting their application-wide use.
  - Refactor existing code for improved clarity, naming consistency, and
    adherence to new naming conventions.
  - Add missing unit tests.
- `UserSelection`:
  - State modifications in `UserSelection` now utilize a singular object
    inspired by the CQRS pattern, enabling batch updates and flexible
    change configurations, thereby simplifying change management.
- Remove the `I` prefix from related interfaces to align with new coding
  standards.
- Refactor related code for better testability in isolation with
  dependency injection.
- Repository:
  - Move repository abstractions to the application layer.
  - Improve repository abstraction to combine `ReadonlyRepository` and
    `MutableRepository` interfaces.
- E2E testing:
  - Introduce E2E tests to validate the correct batch selection
    behavior.
  - Add a specialized data attribute in `TheCodeArea.vue` for improved
    testability.
  - Reorganize shared Cypress functions for a more idiomatic Cypress
    approach.
  - Improve test documentation with related information.
- `SelectedScript`:
  - Create an abstraction for simplified testability.
  - Introduce `SelectedScriptStub` in tests as a substitute for the
    actual object.

tests/unit/application/Common/Timing/PlatformTimer.spec.ts

@@ -0,0 +1,78 @@
+import {
+  describe, it, expect, beforeEach,
+  afterEach,
+} from 'vitest';
+import { PlatformTimer } from '@/application/Common/Timing/PlatformTimer';
+
+describe('PlatformTimer', () => {
+  let originalSetTimeout: typeof global.setTimeout;
+  let originalClearTimeout: typeof global.clearTimeout;
+  let originalDateNow: typeof global.Date.now;
+
+  beforeEach(() => {
+    originalSetTimeout = global.setTimeout;
+    originalClearTimeout = global.clearTimeout;
+    originalDateNow = Date.now;
+    Date.now = () => originalDateNow();
+  });
+
+  afterEach(() => {
+    global.setTimeout = originalSetTimeout;
+    global.clearTimeout = originalClearTimeout;
+    Date.now = originalDateNow;
+  });
+
+  describe('setTimeout', () => {
+    it('calls the global setTimeout with the provided delay', () => {
+      // arrange
+      const expectedDelay = 55;
+      let actualDelay: number | undefined;
+      global.setTimeout = ((_, delay) => {
+        actualDelay = delay;
+      }) as typeof global.setTimeout;
+      // act
+      PlatformTimer.setTimeout(() => { /* NOOP */ }, expectedDelay);
+      // assert
+      expect(actualDelay).to.equal(expectedDelay);
+    });
+    it('calls the global setTimeout with the provided callback', () => {
+      // arrange
+      const expectedCallback = () => { /* NOOP */ };
+      let actualCallback: typeof expectedCallback | undefined;
+      global.setTimeout = ((callback) => {
+        actualCallback = callback;
+      }) as typeof global.setTimeout;
+      // act
+      PlatformTimer.setTimeout(expectedCallback, 33);
+      // assert
+      expect(actualCallback).to.equal(expectedCallback);
+    });
+  });
+
+  describe('clearTimeout', () => {
+    it('should clear timeout', () => {
+      // arrange
+      let actualTimer: ReturnType<typeof PlatformTimer.setTimeout> | undefined;
+      global.clearTimeout = ((timer) => {
+        actualTimer = timer;
+      }) as typeof global.clearTimeout;
+      const expectedTimer = PlatformTimer.setTimeout(() => { /* NOOP */ }, 1);
+      // act
+      PlatformTimer.clearTimeout(expectedTimer);
+      // assert
+      expect(actualTimer).to.equal(expectedTimer);
+    });
+  });
+
+  describe('dateNow', () => {
+    it('should get current date', () => {
+      // arrange
+      const expected = Date.now();
+      Date.now = () => expected;
+      // act
+      const actual = PlatformTimer.dateNow();
+      // assert
+      expect(expected).to.equal(actual);
+    });
+  });
+});