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.ts

@@ -0,0 +1,53 @@
+import { Component, OnInit } from '@angular/core';
+import { CommonModule } from '@angular/common';
+import { RouterOutlet, RouterLink, RouterLinkActive } from '@angular/router';
+import { provideHttpClient } from '@angular/common/http';
+import { ArtifactService } from './services/artifact';
+
+@Component({
+  selector: 'app-root',
+  standalone: true,
+  imports: [CommonModule, RouterOutlet, RouterLink, RouterLinkActive],
+  template: `
+    <div class="container">
+      <header>
+        <h1>◆ Obsidian</h1>
+        <div class="header-info">
+          <span class="badge">{{ deploymentMode }}</span>
+          <span class="badge">{{ storageBackend }}</span>
+        </div>
+      </header>
+
+      <nav class="tabs">
+        <a routerLink="/artifacts" routerLinkActive="active" class="tab-button">
+          📦 Artifacts
+        </a>
+        <a routerLink="/upload" routerLinkActive="active" class="tab-button">
+          📤 Upload
+        </a>
+        <a routerLink="/query" routerLinkActive="active" class="tab-button">
+          🔍 Query
+        </a>
+      </nav>
+
+      <router-outlet></router-outlet>
+    </div>
+  `,
+  styleUrls: ['./app.css']
+})
+export class AppComponent implements OnInit {
+  deploymentMode: string = '';
+  storageBackend: string = '';
+
+  constructor(private artifactService: ArtifactService) {}
+
+  ngOnInit() {
+    this.artifactService.getApiInfo().subscribe({
+      next: (info) => {
+        this.deploymentMode = `Mode: ${info.deployment_mode}`;
+        this.storageBackend = `Storage: ${info.storage_backend}`;
+      },
+      error: (err) => console.error('Failed to load API info:', err)
+    });
+  }
+}