fix(epg): close a guide that never rendered rows without an EmptyError

whenRowsRendered used first(predicate), which errors when the source
completes without a match. The CDK completes renderedRangeStream on
destroy, so closing a guide opened on an empty scope raised an unhandled
EmptyError. Use filter + take(1) instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

libs/ui/epg/src/lib/epg-guide/epg-guide-viewport.controller.spec.ts

@@ -1,7 +1,7 @@
 import { ListRange } from '@angular/cdk/collections';
 import { CdkVirtualScrollViewport } from '@angular/cdk/scrolling';
 import { DestroyRef } from '@angular/core';
-import { Subject } from 'rxjs';
+import { config, Subject } from 'rxjs';
 import { TimelineRenderBlock } from '../epg-timeline/epg-timeline-render.util';
 import { EPG_GUIDE_ROW_BUFFER } from './epg-guide-layout.util';
 import { EpgGuideChannel } from './epg-guide-source';
@@ -220,6 +220,32 @@ describe('EpgGuideViewportController', () => {
         expect(callback).toHaveBeenCalledTimes(1);
     });
 
+    it('closes cleanly when the viewport completes without ever rendering rows', async () => {
+        const test = harness();
+        const callback = jest.fn();
+        const onUnhandledError = jest.fn();
+        const previous = config.onUnhandledError;
+        config.onUnhandledError = onUnhandledError;
+        try {
+            test.controller.whenRowsRendered(
+                test.viewport,
+                test.destroyRef,
+                callback
+            );
+            // An empty scope: the CDK only ever reports an empty range, then
+            // completes the stream when the guide closes.
+            test.renderedRange$.next({ start: 0, end: 0 });
+            test.renderedRange$.complete();
+            // RxJS reports unhandled errors from a timeout.
+            await new Promise((resolve) => setTimeout(resolve, 0));
+        } finally {
+            config.onUnhandledError = previous;
+        }
+
+        expect(onUnhandledError).not.toHaveBeenCalled();
+        expect(callback).not.toHaveBeenCalled();
+    });
+
     it('drops the initial jump when the host is destroyed first', () => {
         const test = harness();
         const callback = jest.fn();

libs/ui/epg/src/lib/epg-guide/epg-guide-viewport.controller.ts

@@ -2,7 +2,7 @@ import { ListRange } from '@angular/cdk/collections';
 import { DestroyRef } from '@angular/core';
 import { CdkVirtualScrollViewport } from '@angular/cdk/scrolling';
 import { takeUntilDestroyed } from '@angular/core/rxjs-interop';
-import { first } from 'rxjs';
+import { filter, take } from 'rxjs';
 import { TimelineRenderBlock } from '../epg-timeline/epg-timeline-render.util';
 import { EpgGuideFocus } from './epg-guide-keyboard.controller';
 import { EPG_GUIDE_ROW_BUFFER } from './epg-guide-layout.util';
@@ -115,7 +115,11 @@ export class EpgGuideViewportController {
     ): void {
         viewport.renderedRangeStream
             .pipe(
-                first((range) => range.end > range.start),
+                // Not `first(predicate)`: the CDK completes the stream on
+                // destroy, and a guide closed without ever having rows would
+                // then raise an `EmptyError`.
+                filter((range) => range.end > range.start),
+                take(1),
                 takeUntilDestroyed(destroyRef)
             )
             .subscribe(() => callback());