fix(playback): decide an edge press from the panel state at pointerdown

A press held on the edge past the hover dwell opened the panel before the
release, which then read the open state and dismissed it. The press now
remembers whether it began on an open panel.

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

libs/ui/playback/src/lib/fullscreen-channel-panel/fullscreen-channel-panel.component.spec.ts

@@ -558,6 +558,21 @@ describe('FullscreenChannelPanelComponent', () => {
         expect(query('host-list')).not.toBeNull();
     });
 
+    it('keeps the panel open when the hover dwell opens it during a held press', () => {
+        setFullscreen(stage);
+        stage.dispatchEvent(pointerEvent('pointermove'));
+        hotZone()?.dispatchEvent(pointerEvent('pointerenter'));
+        hotZone()?.dispatchEvent(pointerEvent('pointerdown'));
+        jest.advanceTimersByTime(CHANNEL_PANEL_OPEN_DWELL_MS);
+        fixture.detectChanges();
+        expect(isOpen()).toBe(true);
+
+        hotZone()?.dispatchEvent(pointerEvent('pointerup'));
+        fixture.detectChanges();
+
+        expect(isOpen()).toBe(true);
+    });
+
     it('closes on the scrim but keeps the list mounted for the next opening', () => {
         setFullscreen(stage);
         openByHover();

libs/ui/playback/src/lib/fullscreen-channel-panel/fullscreen-channel-panel.component.ts

@@ -151,6 +151,12 @@ export class FullscreenChannelPanelComponent implements OnDestroy {
 
     /** Pointer whose primary press began inside the hot zone, if any. */
     private hotZonePressPointerId: number | null = null;
+    /**
+     * Whether that press began on an open panel. Decided at pointerdown: the
+     * hover dwell can open the panel while the button is still held, and that
+     * release must not read as a dismissal.
+     */
+    private hotZonePressBeganOpen = false;
 
     private readonly onDocumentKeydown = (event: KeyboardEvent) =>
         this.handleKeydown(event);
@@ -236,6 +242,7 @@ export class FullscreenChannelPanelComponent implements OnDestroy {
     onHotZonePointerDown(event: PointerEvent): void {
         this.hotZonePressPointerId =
             event.button === 0 ? event.pointerId : null;
+        this.hotZonePressBeganOpen = this.state.open();
     }
 
     onHotZonePointerUp(event: PointerEvent): void {
@@ -244,7 +251,7 @@ export class FullscreenChannelPanelComponent implements OnDestroy {
         if (pressed === null || pressed !== event.pointerId) {
             return;
         }
-        if (this.state.open()) {
+        if (this.hotZonePressBeganOpen) {
             this.state.hide();
             return;
         }