test(angular): resolve flaky explorer tests and fix text renderer stringification

- Statically import and provide @a2ui/markdown-it in test_utils.ts to avoid dynamic import chunk loading latency under Karma headless browsers in resource-constrained CI.

- Ensure TextComponent (v0.9) converts the text prop value to a string before passing to the Markdown renderer, preventing validation failures on numeric bound properties.

Author: josemontespg

renderers/angular/a2ui_explorer/src/app/tests/utils/test_utils.ts

@@ -19,6 +19,7 @@ import {DemoComponent} from '../../demo.component';
 import {EXAMPLES_V08, EXAMPLES_V09} from '../../generated/examples-bundle';
 import {provideMarkdownRenderer} from '../../../../../src/v0_9/core/markdown';
 import {A2UI_VERSION, Version} from '../../types';
+import {renderMarkdown} from '@a2ui/markdown-it';
 
 export {Version};
 
@@ -30,7 +31,9 @@ export async function loadExample(exampleName: string, version: Version = Versio
   await TestBed.configureTestingModule({
     imports: [DemoComponent],
     providers: [
-      provideMarkdownRenderer(),
+      provideMarkdownRenderer(async (markdown, options) =>
+        renderMarkdown(markdown, options as any),
+      ),
       {
         provide: A2UI_VERSION,
         useValue: version,

renderers/angular/src/v0_9/catalog/basic/text.component.ts

@@ -108,7 +108,10 @@ export class TextComponent extends BasicCatalogComponent<typeof TextApi> {
   private markdownRenderer = inject(MarkdownRenderer);
 
   readonly variant = computed(() => this.props()['variant']?.value() || 'body');
-  readonly text = computed(() => this.props()['text']?.value() || '');
+  readonly text = computed(() => {
+    const val = this.props()['text']?.value();
+    return val == null ? '' : String(val);
+  });
 
   resolvedText = signal<string>('');
   private renderRequestId = 0;