Add order and performance info components to ticket overlay

Introduces OrderComponent, PerformanceInfoComponent, and ShoppingCartComponent for the ticket purchase flow. Updates theater-overlay to display seat selection alongside order details and performance info. Refactors seat and performance data loading, improves UI structure, and enhances movie info display components for consistency.

src/app/performance-info/performance-info.component.ts

@@ -0,0 +1,30 @@
+import { Component, computed, input } from '@angular/core';
+import { Vorstellung } from '@infinimotion/model-frontend';
+
+@Component({
+  selector: 'app-performance-info',
+  standalone: false,
+  templateUrl: './performance-info.component.html',
+  styleUrl: './performance-info.component.css'
+})
+export class PerformanceInfoComponent {
+  performance = input.required<Vorstellung>();
+
+  getStartTimeString(): string {
+    const date = new Date(this.performance().start);
+    return date.toLocaleDateString('de-DE', { weekday: 'short' }) + '. ' + date.toLocaleDateString('de-DE') + ', ' +  date.toLocaleTimeString('de-DE', { hour: '2-digit', minute: '2-digit' }) + ' Uhr';
+  }
+
+  movie() {
+    return this.performance().movie
+  }
+
+  onPosterError(event: Event) {
+    const img = event.target as HTMLImageElement;
+    const placeholder = 'assets/poster_placeholder.png';
+
+    if (img.src !== window.location.origin + placeholder) {
+      img.src = placeholder;
+    }
+  }
+}