Refactor API and enhance Angular integration

- Removed `ciTargetName` from `nx.json`.
- Updated `package.json` to include new dependencies: `@types/seedrandom`, `fast-check`, `happy-dom`, and `@nestjs/schedule`.
- Modified `pnpm-lock.yaml` to reflect the addition of new packages and their versions.
- Improved project documentation in `PROJECT_CONTEXT.md` to clarify the use of Zod schemas and Angular framework decisions.
- Introduced new Angular components and patterns in the `.agents/skills/frontend-angular` directory, including examples and reference materials for Angular 21+ features.

.claude/skills/frontend-angular/SKILL.md

@@ -0,0 +1,190 @@
+---
+name: frontend-angular
+description: Modern Angular 21+ patterns including signals, standalone components, zoneless change detection, and new control flow syntax. Use for Angular architecture decisions or implementing components with latest APIs.
+trigger-terms: Angular 21+, signals, standalone components, zoneless, control flow, @if, @for
+---
+
+# Angular Production Patterns
+
+Production-ready patterns for Angular 21+ applications with zoneless change detection.
+
+## Core Concepts
+
+### Signal-Based Reactivity
+
+```typescript
+import { Component, signal, computed, effect } from '@angular/core';
+
+@Component({
+  selector: 'app-counter',
+  standalone: true,
+  template: `
+    <button (click)="increment()">
+      {{ count() }} × 2 = {{ doubled() }}
+    </button>
+  `
+})
+export class CounterComponent {
+  count = signal(0);
+  doubled = computed(() => this.count() * 2);
+
+  constructor() {
+    effect(() => console.log('Count changed:', this.count()));
+  }
+
+  increment() {
+    this.count.update(n => n + 1);
+  }
+}
+```
+
+### Key APIs
+
+| API | Purpose |
+|-----|---------|
+| `signal()` | Reactive state declaration |
+| `computed()` | Derived values (auto-tracked) |
+| `effect()` | Side effects on signal changes |
+| `input()` | Component inputs (replaces @Input) |
+| `output()` | Component outputs (replaces @Output) |
+| `model()` | Two-way bindable signals |
+
+## Modern Control Flow
+
+```html
+<!-- Conditionals -->
+@if (isLoading()) {
+  <app-spinner />
+} @else if (hasError()) {
+  <app-error [message]="error()" />
+} @else {
+  <app-content [data]="data()" />
+}
+
+<!-- Loops with tracking -->
+@for (item of items(); track item.id) {
+  <app-item [data]="item" />
+} @empty {
+  <p>No items found</p>
+}
+
+<!-- Switch -->
+@switch (status()) {
+  @case ('pending') { <app-pending /> }
+  @case ('active') { <app-active /> }
+  @default { <app-unknown /> }
+}
+```
+
+## Standalone Architecture
+
+```typescript
+// No NgModules - components declare their dependencies
+@Component({
+  selector: 'app-dashboard',
+  standalone: true,
+  imports: [CommonModule, RouterModule, MetricsComponent],
+  template: `...`
+})
+export class DashboardComponent {}
+
+// Bootstrapping
+bootstrapApplication(AppComponent, {
+  providers: [
+    provideRouter(routes),
+    provideHttpClient(withInterceptors([authInterceptor]))
+  ]
+});
+```
+
+## Component I/O (Angular 21+)
+
+```typescript
+@Component({...})
+export class UserCardComponent {
+  // Input signal (required)
+  user = input.required<User>();
+
+  // Input with default
+  showAvatar = input(true);
+
+  // Output
+  selected = output<User>();
+
+  // Two-way binding
+  isExpanded = model(false);
+
+  onSelect() {
+    this.selected.emit(this.user());
+  }
+}
+```
+
+## Performance Targets
+
+| Metric | Target |
+|--------|--------|
+| LCP | < 2.5s |
+| INP | < 200ms |
+| CLS | < 0.1 |
+| Initial Bundle | < 250KB |
+
+## When NOT to Use Angular
+
+- Simple interactivity → Vanilla JS
+- Static marketing site → Astro/11ty
+- < 100KB JS budget → Svelte or Web Components
+- React ecosystem dependency → React
+
+## Signal Testing Patterns
+
+| Pattern | Use Case |
+|---------|----------|
+| PLATFORM_ID mocking | Prevent constructor side effects in SSR tests |
+| WritableSignal with `.set()` | Control signal state without reassignment |
+| NG0100 prevention | Initialize signals before `detectChanges()` |
+
+## Signal-Based Service Pattern
+
+Private writable signal → public readonly → update in `tap()` → component injects and reads:
+
+```typescript
+@Injectable({ providedIn: 'root' })
+export class AnalyticsService {
+  private _summary = signal<Summary | null>(null);
+  readonly summary = this._summary.asReadonly();
+
+  private _loading = signal(false);
+  readonly loading = this._loading.asReadonly();
+
+  getSummary() {
+    this._loading.set(true);
+    return this.http.get<Summary>('/api/analytics/summary').pipe(
+      tap(data => {
+        this._summary.set(data);
+        this._loading.set(false);
+      }),
+      catchError(err => {
+        this._loading.set(false);
+        throw err;
+      })
+    );
+  }
+}
+```
+
+**Component usage:**
+```typescript
+@Component({...})
+export class DashboardComponent {
+  private analytics = inject(AnalyticsService);
+  summary = this.analytics.summary;
+  loading = this.analytics.loading;
+}
+```
+
+**Pattern:** Matches AuthService pattern for consistency across services.
+
+See `examples.md` for full testing code patterns.
+
+See `reference.md` for component libraries.