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/CategoryStub.ts

@@ -12,6 +12,8 @@ export class CategoryStub extends BaseEntity<number> implements ICategory {
 
   public readonly docs = new Array<string>();
 
+  private allScriptsRecursively: (readonly IScript[]) | undefined;
+
   public constructor(id: number) {
     super(id);
   }
@@ -21,13 +23,16 @@ export class CategoryStub extends BaseEntity<number> implements ICategory {
   }
 
   public getAllScriptsRecursively(): readonly IScript[] {
-    return [
-      ...this.scripts,
-      ...this.subCategories.flatMap((c) => c.getAllScriptsRecursively()),
-    ];
+    if (this.allScriptsRecursively === undefined) {
+      return [
+        ...this.scripts,
+        ...this.subCategories.flatMap((c) => c.getAllScriptsRecursively()),
+      ];
+    }
+    return this.allScriptsRecursively;
   }
 
-  public withScriptIds(...scriptIds: string[]): this {
+  public withScriptIds(...scriptIds: readonly string[]): this {
     return this.withScripts(
       ...scriptIds.map((id) => new ScriptStub(id)),
     );
@@ -40,6 +45,15 @@ export class CategoryStub extends BaseEntity<number> implements ICategory {
     return this;
   }
 
+  public withAllScriptIdsRecursively(...scriptIds: readonly string[]): this {
+    return this.withAllScriptsRecursively(...scriptIds.map((id) => new ScriptStub(id)));
+  }
+
+  public withAllScriptsRecursively(...scripts: IScript[]): this {
+    this.allScriptsRecursively = [...scripts];
+    return this;
+  }
+
   public withMandatoryScripts(): this {
     return this
       .withScript(new ScriptStub(`[${CategoryStub.name}] script-1`).withLevel(RecommendationLevel.Standard))