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/shared/Stubs/BatchedDebounceStub.ts

@@ -0,0 +1,33 @@
+import { batchedDebounce } from '@/application/Common/Timing/BatchedDebounce';
+
+export class BatchedDebounceStub<T> {
+  public readonly callHistory = new Array<Parameters<typeof batchedDebounce>>();
+
+  public readonly collectedArgs = new Array<T>();
+
+  private executeImmediately = false;
+
+  public func = (
+    callback: (batches: readonly T[]) => void,
+    waitInMs: number,
+  ): (arg: T) => void => {
+    this.callHistory.push([callback, waitInMs]);
+    return (arg: T) => {
+      this.collectedArgs.push(arg);
+      if (this.executeImmediately) {
+        callback([arg]);
+      }
+    };
+  };
+
+  public withImmediateDebouncing(executeImmediately: boolean): this {
+    this.executeImmediately = executeImmediately;
+    return this;
+  }
+
+  public execute() {
+    this.callHistory
+      .map((call) => call[0])
+      .forEach((callback) => callback(this.collectedArgs));
+  }
+}