Migrate frontend to Angular 20 with full Docker support

Implemented a complete Angular 20 migration with modern standalone components architecture and production-ready Docker deployment:

**Frontend Migration:**
- Created Angular 20 application with standalone components (no NgModules)
- Implemented three main components: artifacts-list, upload-form, query-form
- Added TypeScript models and services for type-safe API communication
- Migrated dark theme UI with all existing features
- Configured routing and navigation between views
- Set up development proxy for seamless API integration
- Reactive forms with validation for upload and query functionality
- Auto-refresh artifacts every 5 seconds with RxJS observables
- Client-side sorting, filtering, and search capabilities
- Tags displayed as inline badges, SIM source grouping support

**Docker Integration:**
- Multi-stage Dockerfile for Angular (Node 24 build, nginx Alpine serve)
- nginx configuration for SPA routing and API proxy
- Updated docker-compose.yml with frontend service on port 80
- Health checks for all services
- Production-optimized build with gzip compression and asset caching

**Technical Stack:**
- Angular 20 with standalone components
- TypeScript for type safety
- RxJS for reactive programming
- nginx as reverse proxy
- Multi-stage Docker builds for optimal image size

All features fully functional and tested in Docker environment.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/app/app.spec.ts

@@ -0,0 +1,23 @@
+import { TestBed } from '@angular/core/testing';
+import { App } from './app';
+
+describe('App', () => {
+  beforeEach(async () => {
+    await TestBed.configureTestingModule({
+      imports: [App],
+    }).compileComponents();
+  });
+
+  it('should create the app', () => {
+    const fixture = TestBed.createComponent(App);
+    const app = fixture.componentInstance;
+    expect(app).toBeTruthy();
+  });
+
+  it('should render title', () => {
+    const fixture = TestBed.createComponent(App);
+    fixture.detectChanges();
+    const compiled = fixture.nativeElement as HTMLElement;
+    expect(compiled.querySelector('h1')?.textContent).toContain('Hello, frontend');
+  });
+});