fix(m3u): keep the sidebar mounted while the guide is open

Guide mode wrapped the sidebar in `@if (!guideOpen())`, so opening the
guide destroyed `app-channel-list-container`, whose `ngOnDestroy`
dispatches `resetActiveChannel()`. That cleared the active channel, which
unmounted the block hosting `app-epg-guide` and tripped the
`!canOpenGuide()` effect into closing the guide again: the guide never
appeared and the page dropped to "Please select a channel".

The sidebar now stays mounted and is hidden with
`.sidebar--guide-hidden` plus `inert`, so it is neither focusable nor read
by assistive technology while the guide owns the layout. Hiding also
preserves the channel list's scroll position across guide toggles.

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

libs/playlist/m3u/feature-player/src/lib/video-player/video-player.component.html

@@ -1,55 +1,62 @@
-@if (!guideOpen()) {
-    <div
-        class="sidebar"
-        [class.sidebar-collapsed]="isSidebarCollapsed()"
-        appResizable
-        [minWidth]="sidebarMinWidth"
-        [maxWidth]="sidebarMaxWidth"
-        [defaultWidth]="sidebarWidth()"
-        [style.width.px]="sidebarWidth()"
-        [storageKey]="sidebarStorageKey()"
-        (widthChange)="onSidebarWidthChange($event)"
-        (resizeEnd)="onSidebarResizeEnd($event)"
-    >
-        @if (activeView() !== 'groups' && activeView() !== 'all') {
-            <button
-                mat-icon-button
-                type="button"
-                class="sidebar-collapse-toggle"
-                [attr.aria-label]="'LAYOUT.HIDE_CHANNELS_LIST' | translate"
-                [matTooltip]="'LAYOUT.TOGGLE_SIDEBAR_TOOLTIP' | translate"
-                [attr.aria-pressed]="isSidebarCollapsed()"
-                (click)="toggleSidebar()"
-            >
-                <mat-icon>chevron_left</mat-icon>
-            </button>
-        }
-        @defer {
-            <app-sidebar
-                [channels]="(channels$ | async)!"
-                [channelsLoading]="channelsLoading()"
-                [showPlaylistHeader]="!isWorkspaceLayout"
-                [activeView]="activeView()"
-                [sidebarWidth]="sidebarWidth()"
-                (sidebarWidthRequested)="onGroupedSidebarWidthRequested($event)"
-                (sidebarWidthRequestEnded)="
-                    onGroupedSidebarWidthRequestEnded($event)
-                "
-                (sidebarToggleRequested)="toggleSidebar()"
-            />
-        } @loading {
-            <app-channel-list-loading-state
-                [view]="activeView()"
-                [showEpg]="supportsEpg"
-            />
-        } @placeholder {
-            <app-channel-list-loading-state
-                [view]="activeView()"
-                [showEpg]="supportsEpg"
-            />
-        }
-    </div>
-}
+<!--
+    Guide mode HIDES this sidebar instead of removing it: destroying it would
+    destroy `app-channel-list-container`, whose `ngOnDestroy` dispatches
+    `resetActiveChannel()` — that clears the active channel the guide itself
+    needs, so the guide would close again the moment it opened. `inert` keeps
+    the hidden rail out of the tab order and away from assistive technology.
+-->
+<div
+    class="sidebar"
+    [class.sidebar-collapsed]="isSidebarCollapsed()"
+    [class.sidebar--guide-hidden]="guideOpen()"
+    [attr.inert]="guideOpen() ? '' : null"
+    appResizable
+    [minWidth]="sidebarMinWidth"
+    [maxWidth]="sidebarMaxWidth"
+    [defaultWidth]="sidebarWidth()"
+    [style.width.px]="sidebarWidth()"
+    [storageKey]="sidebarStorageKey()"
+    (widthChange)="onSidebarWidthChange($event)"
+    (resizeEnd)="onSidebarResizeEnd($event)"
+>
+    @if (activeView() !== 'groups' && activeView() !== 'all') {
+        <button
+            mat-icon-button
+            type="button"
+            class="sidebar-collapse-toggle"
+            [attr.aria-label]="'LAYOUT.HIDE_CHANNELS_LIST' | translate"
+            [matTooltip]="'LAYOUT.TOGGLE_SIDEBAR_TOOLTIP' | translate"
+            [attr.aria-pressed]="isSidebarCollapsed()"
+            (click)="toggleSidebar()"
+        >
+            <mat-icon>chevron_left</mat-icon>
+        </button>
+    }
+    @defer {
+        <app-sidebar
+            [channels]="(channels$ | async)!"
+            [channelsLoading]="channelsLoading()"
+            [showPlaylistHeader]="!isWorkspaceLayout"
+            [activeView]="activeView()"
+            [sidebarWidth]="sidebarWidth()"
+            (sidebarWidthRequested)="onGroupedSidebarWidthRequested($event)"
+            (sidebarWidthRequestEnded)="
+                onGroupedSidebarWidthRequestEnded($event)
+            "
+            (sidebarToggleRequested)="toggleSidebar()"
+        />
+    } @loading {
+        <app-channel-list-loading-state
+            [view]="activeView()"
+            [showEpg]="supportsEpg"
+        />
+    } @placeholder {
+        <app-channel-list-loading-state
+            [view]="activeView()"
+            [showEpg]="supportsEpg"
+        />
+    }
+</div>
 
 <div
     class="content-container"

libs/playlist/m3u/feature-player/src/lib/video-player/video-player.component.scss

@@ -147,6 +147,17 @@
 }
 
 // ─── Guide mode ─────────────────────────────────────────────────────────────
+// The sidebar stays MOUNTED while the guide is open and is only hidden: its
+// channel-list container dispatches `resetActiveChannel()` from `ngOnDestroy`,
+// so removing it would clear the active channel the guide needs and close the
+// guide again. `!important` beats the resizable directive's inline width, and
+// it is declared after the phone breakpoint so the bottom-drawer rules
+// (`height: 50vh`, borders) cannot leave a phantom band on small screens.
+// Hiding rather than removing also preserves the list's scroll position.
+.sidebar.sidebar--guide-hidden {
+    display: none !important;
+}
+
 // The player keeps its DOM position and is only re-flowed into a docked strip;
 // no remount, so playback (and native-view Embedded MPV bounds) survive.
 .content-container.is-guide {

libs/playlist/m3u/feature-player/src/lib/video-player/video-player.component.spec.ts

@@ -273,7 +273,7 @@ describe('VideoPlayerComponent', () => {
         expect(headerContext.action()).toBeNull();
     });
 
-    it('opens the guide in place of sidebar and timeline without remounting the player', () => {
+    it('opens the guide, hides the sidebar without unmounting it, and keeps the player', () => {
         syncStoreState(sampleChannel);
         player.set(VideoPlayer.VideoJs);
         fixture.detectChanges();
@@ -284,7 +284,9 @@ describe('VideoPlayerComponent', () => {
         expect(
             fixture.nativeElement.querySelector('app-epg-timeline')
         ).not.toBeNull();
-        expect(fixture.nativeElement.querySelector('.sidebar')).not.toBeNull();
+        const sidebarBefore = fixture.nativeElement.querySelector('.sidebar');
+        expect(sidebarBefore).not.toBeNull();
+        storeMock.dispatch.mockClear();
 
         component.openGuide();
         fixture.detectChanges();
@@ -295,7 +297,18 @@ describe('VideoPlayerComponent', () => {
         expect(
             fixture.nativeElement.querySelector('app-epg-guide-now-playing')
         ).not.toBeNull();
-        expect(fixture.nativeElement.querySelector('.sidebar')).toBeNull();
+        // Regression: the sidebar used to sit behind `@if (!guideOpen())`, so
+        // opening the guide destroyed the channel-list container, whose
+        // `ngOnDestroy` dispatches `resetActiveChannel()`. That cleared the
+        // active channel and closed the guide again the moment it opened.
+        expect(storeMock.dispatch).not.toHaveBeenCalledWith(
+            ChannelActions.resetActiveChannel()
+        );
+        const sidebarWhileOpen =
+            fixture.nativeElement.querySelector('.sidebar');
+        expect(sidebarWhileOpen).toBe(sidebarBefore);
+        expect(sidebarWhileOpen.classList).toContain('sidebar--guide-hidden');
+        expect(sidebarWhileOpen.hasAttribute('inert')).toBe(true);
         expect(
             fixture.nativeElement.querySelector('app-epg-timeline')
         ).toBeNull();
@@ -310,9 +323,10 @@ describe('VideoPlayerComponent', () => {
         component.closeGuide();
         fixture.detectChanges();
         expect(fixture.nativeElement.querySelector('app-epg-guide')).toBeNull();
-        // The sidebar list itself sits behind an `@defer`, so the assertion
-        // targets the container the guide mode actually removes.
-        expect(fixture.nativeElement.querySelector('.sidebar')).not.toBeNull();
+        const sidebarAfter = fixture.nativeElement.querySelector('.sidebar');
+        expect(sidebarAfter).toBe(sidebarBefore);
+        expect(sidebarAfter.classList).not.toContain('sidebar--guide-hidden');
+        expect(sidebarAfter.hasAttribute('inert')).toBe(false);
         expect(fixture.nativeElement.querySelector('app-web-player-view')).toBe(
             playerBefore
         );