Add IMDb movie importer feature and unify header

Introduces a new movie importer feature allowing admins to search and import movies from IMDb, including new components for search, result display, and error handling. Replaces the schedule header with a reusable menu header component. Updates routing, navigation, and HTTP service to support the new importer. Adds a poster placeholder image and improves poster error handling.

src/app/movie-import-search-info/movie-import-search-info.component.ts

@@ -0,0 +1,68 @@
+import { Component, inject, input } from '@angular/core';
+import { Film, OmdbMovie } from '@infinimotion/model-frontend';
+import { HttpService } from '../http.service';
+import { LoadingService } from '../loading.service';
+import { catchError, EMPTY, of, switchMap, tap } from 'rxjs';
+
+@Component({
+  selector: 'app-movie-import-search-info',
+  standalone: false,
+  templateUrl: './movie-import-search-info.component.html',
+  styleUrl: './movie-import-search-info.component.css'
+})
+export class MovieImportSearchInfoComponent {
+  readonly movie = input.required<OmdbMovie>();
+
+  importedMovie: Film | undefined;
+  buttonDisabled = false;
+  buttonText: string = "Film von IMDb importieren";
+  buttonIcon: string = "cloud_download"
+
+  private http = inject(HttpService)
+  private loading = inject(LoadingService)
+
+  importMovie(imdbId: string, title: string) {
+    this.buttonDisabled = true;
+    this.loading.show();
+
+    const filter = this.generateTitleFilter(title);
+
+    this.http.getMoviesByFilter(filter).pipe(
+      switchMap(movies => {
+        if (movies.length !== 0) {
+          this.loading.showError(`Dublette erkannt! Film '${title}' existiert bereits.`);
+          console.warn('Dublette erkannt. Import abgebrochen.');
+          this.buttonText = 'Film existiert bereits'
+          this.buttonIcon = 'file_present';
+          return EMPTY;
+        }
+        return this.http.importMovie(imdbId);
+      }),
+      tap(importedMovie => {
+        this.importedMovie = importedMovie;
+        this.buttonText = `Film erfolgreich importiert (Id: ${importedMovie.id})`;
+        this.buttonIcon = 'cloud_done';
+        this.loading.hide();
+      }),
+      catchError(err => {
+        this.buttonDisabled = false;
+        this.loading.showError(err);
+        console.error('Fehler beim Import oder bei der Dublettenprüfung', err);
+        return of([]);
+      })
+    ).subscribe();
+  }
+
+  private generateTitleFilter(title: string): string[] {
+    return [`eq;title;string;${title}`]
+  }
+
+  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;
+    }
+  }
+}