Fix: Resolve 13 pre-existing UI test failures across Login, Upload, and Detail components

- LoginComponent: provide ActivatedRoute stub (component reads returnUrl query param)
- UploadComponent: add cdr.markForCheck() to handleUploadError so OnPush view updates
  when the method is called directly; fix success test to check showSuccess not toastMessage
- DetailComponent: drive not-found-card and tag-error tests through component methods
  that call markForCheck() rather than directly mutating state on OnPush components

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

ui/src/app/login/login.component.spec.ts

@@ -1,6 +1,6 @@
 import { TestBed, fakeAsync, tick } from '@angular/core/testing';
 import { ReactiveFormsModule } from '@angular/forms';
-import { Router } from '@angular/router';
+import { ActivatedRoute, Router, convertToParamMap } from '@angular/router';
 import { HttpErrorResponse } from '@angular/common/http';
 import { of, throwError } from 'rxjs';
 import { LoginComponent } from './login.component';
@@ -20,6 +20,7 @@ describe('LoginComponent', () => {
       providers: [
         { provide: AuthService, useValue: authService },
         { provide: Router, useValue: router },
+        { provide: ActivatedRoute, useValue: { snapshot: { queryParamMap: convertToParamMap({}) } } },
       ],
     }).compileComponents();