feat: set up Angular infrastructure for TableWidget

[shuoweil]

Initialized an Angular workspace within bigframes/display/table_widget_angular and configured a custom build pipeline using esbuild to generate a single-file ESM output. This establishes the infrastructure required for the planned Angular hybrid approach for TableWidget.

Fixes #<505414691> 🦕

[gemini-code-assist]

Code Review

This pull request adds a new Angular-based hybrid widget to the bigframes package, utilizing anywidget for Python-to-JavaScript communication. The feedback highlights critical issues with dependency versioning in package.json and README.md, where non-existent future versions of Angular and TypeScript are specified. There are also several unused boilerplate files and redundant imports that should be cleaned up. Furthermore, the unit tests need to be corrected to include the required injection tokens and reflect the actual component template structure.

[gemini-code-assist]

The version numbers specified for several dependencies (Angular, TypeScript, Vitest) and the packageManager (npm) refer to non-existent future releases (e.g., Angular ^21.2.0, TypeScript ~5.9.2, npm 11.7.0). As of now, the latest stable version of Angular is 19. Using these invalid versions will cause installation and build failures.

[shuoweil]

Upon verification, those versions are existing.

[gemini-code-assist]

The unit tests will fail because the App component requires the ANYWIDGET_MODEL token to be provided for injection, and the DOM expectation in the second test looks for an h1 element and text that are not present in the component's actual template (which uses an h3).

describe('App', () => {
  beforeEach(async () => {
    await TestBed.configureTestingModule({
      imports: [App],
      providers: [{ provide: 'ANYWIDGET_MODEL', useValue: null }]
    }).compileComponents();
  });

  it('should create the app', () => {
    const fixture = TestBed.createComponent(App);
    const app = fixture.componentInstance;
    expect(app).toBeTruthy();
  });

  it('should render title', async () => {
    const fixture = TestBed.createComponent(App);
    fixture.detectChanges();
    const compiled = fixture.nativeElement as HTMLElement;
    expect(compiled.querySelector('h3')?.textContent).toContain('Angular Hybrid Widget');
  });
});

[shuoweil]

Fixed. I have added the provider for ANYWIDGET_MODEL in the test setup and updated the expectations to look for h3 and match the component's template content. The unit tests are now passing successfully.

[gemini-code-assist]

This file contains the default Angular boilerplate template but is not used by the App component, which defines its template inline in app.ts. It should be removed to keep the project clean.

[shuoweil]

Addressed. I have deleted app.html as the component uses an inline template.

[gemini-code-assist]

This file is unused. The application configuration is defined locally within the render function in src/main.ts to facilitate the anywidget integration.

[shuoweil]

Addressed. I have deleted app.config.ts to keep the project clean since the configuration is managed in src/main.ts

[gemini-code-assist]

CommonModule is imported and included in the imports array but is not used in the component's template. It can be safely removed along with its import statement on line 2.

Suggested change

	imports: [CommonModule],
	imports: [],

[shuoweil]

Addressed. I have removed CommonModule from the imports to keep the component lightweight.

[gemini-code-assist]

The Angular CLI version mentioned (21.2.9) does not exist. Please update this to reflect the actual version used (likely 19.x).

[shuoweil]

Addressed. I have removed CommonModule from the imports to keep the component lightweight.