Add CRT shader toggle to player settings menu

Adds a per-session CRT-Lottes shader toggle in the video player settings
menu (shown when transcoding is available). Toggling restarts the stream
with streamOptions[crtShader]=true appended to the TranscodingUrl, which
the server picks up to apply the OpenCL CRT post-processing filter.

- playersettingsmenu: showCrtMenu() (On/Off actionsheet), menu entry with
  current state as aside text, handleSelectedOption case
- playbackmanager: isCrtShaderEnabled(), setCrtShader(enabled, shadowMask)
  methods; createStreamInfo appends CRT stream options to TranscodingUrl

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/components/playback/playbackmanager.js

@@ -1422,6 +1422,21 @@ export class PlaybackManager {
             });
         };
 
+        self.isCrtShaderEnabled = function (player) {
+            player = player || self._currentPlayer;
+            return !!(getPlayerData(player).enableCrtShader);
+        };
+
+        self.setCrtShader = function (enabled, shadowMask, player) {
+            player = player || self._currentPlayer;
+            const pd = getPlayerData(player);
+            pd.enableCrtShader = !!enabled;
+            if (shadowMask !== undefined && shadowMask !== null) {
+                pd.crtShadowMask = shadowMask;
+            }
+            changeStream(player, getCurrentTicks(player), {});
+        };
+
         self.isFullscreen = function (player) {
             player = player || self._currentPlayer;
             if (!player.isLocalPlayer || player.isFullscreen) {
@@ -2856,7 +2871,19 @@ export class PlaybackManager {
 
                     playMethod = mediaSource.SupportsDirectPlay ? 'DirectPlay' : 'DirectStream';
                 } else if (mediaSource.SupportsTranscoding) {
-                    mediaUrl = apiClient.getUrl(mediaSource.TranscodingUrl);
+                    let transcodingUrl = mediaSource.TranscodingUrl;
+
+                    // Append CRT-Lottes shader option when enabled for this session.
+                    if (getPlayerData(player).enableCrtShader) {
+                        const sep = transcodingUrl.includes('?') ? '&' : '?';
+                        transcodingUrl += sep + 'streamOptions%5BcrtShader%5D=true';
+                        const maskVal = getPlayerData(player).crtShadowMask;
+                        if (maskVal !== undefined && maskVal !== null) {
+                            transcodingUrl += '&streamOptions%5BcrtShadowMask%5D=' + maskVal;
+                        }
+                    }
+
+                    mediaUrl = apiClient.getUrl(transcodingUrl);
 
                     if (mediaSource.TranscodingSubProtocol === 'hls') {
                         contentType = 'application/x-mpegURL';

src/components/playback/playersettingsmenu.js

@@ -4,6 +4,34 @@ import globalize from 'lib/globalize';
 import { ServerConnections } from 'lib/jellyfin-apiclient';
 import qualityoptions from '../qualityOptions';
 
+function showCrtMenu(player, btn) {
+    const isEnabled = playbackManager.isCrtShaderEnabled(player);
+
+    const menuItems = [
+        {
+            name: globalize.translate('On'),
+            id: 'crt_on',
+            selected: isEnabled
+        },
+        {
+            name: globalize.translate('Off'),
+            id: 'crt_off',
+            selected: !isEnabled
+        }
+    ];
+
+    return actionsheet.show({
+        items: menuItems,
+        positionTo: btn
+    }).then(function (id) {
+        if (id === 'crt_on' && !isEnabled) {
+            playbackManager.setCrtShader(true, null, player);
+        } else if (id === 'crt_off' && isEnabled) {
+            playbackManager.setCrtShader(false, null, player);
+        }
+    });
+}
+
 function showQualityMenu(player, btn) {
     const videoStream = playbackManager.currentMediaSource(player).MediaStreams.filter(function (stream) {
         return stream.Type === 'Video';
@@ -214,6 +242,16 @@ function showWithUser(options, player, user) {
         });
     }
 
+    if (options.quality && user?.Policy?.EnableVideoPlaybackTranscoding) {
+        menuItems.push({
+            name: 'CRT Shader',
+            id: 'crtshader',
+            asideText: playbackManager.isCrtShaderEnabled(player)
+                ? globalize.translate('On')
+                : globalize.translate('Off')
+        });
+    }
+
     const repeatMode = playbackManager.getRepeatMode(player);
 
     if (supportedCommands.indexOf('SetRepeatMode') !== -1 && playbackManager.currentMediaSource(player).RunTimeTicks) {
@@ -272,6 +310,8 @@ function handleSelectedOption(id, options, player) {
             return showPlaybackRateMenu(player, options.positionTo);
         case 'repeatmode':
             return showRepeatModeMenu(player, options.positionTo);
+        case 'crtshader':
+            return showCrtMenu(player, options.positionTo);
         case 'stats':
             if (options.onOption) {
                 options.onOption('stats');