feat(media): add toggle for album art accent colors (#2831) (#2832)

* fix(media): use system colours in player instead of album cover accent

Closes #2831

Removes ColorQuantizer-based album art accent extraction from
MediaAccentService. All accent properties now return Theme.primary
and Theme.onPrimary directly, so the Dank Dash player always
matches the system colour scheme.

Blame: ee6f7b47 (introduced MediaAccentService & ColorQuantizer)
       d799175c (tweaked seekbar accent colours)
       a62ae336 (further integrated accent into player/album art)
       c44ffae7 (monochrome art edge case fixes)

* feat(media): add toggle for album art accent colours (#2831)

Adds mediaUseAlbumArtAccent setting (default: off) to Settings.
When enabled, MediaAccentService extracts accent from album art
via ColorQuantizer. When disabled, uses Theme.primary.
Toggle is in Settings > Media Player.

* fix: use american english spelling (colour -> color)

Port 1.5

quickshell/Common/SettingsData.qml

@@ -455,6 +455,7 @@ Singleton {
     property bool scrollTitleEnabled: true
     property bool mediaAdaptiveWidthEnabled: true
     property bool audioVisualizerEnabled: true
+    property bool mediaUseAlbumArtAccent: false
     property string audioScrollMode: "volume"
     property int audioWheelScrollAmount: 5
     property bool audioDeviceScrollVolumeEnabled: false

quickshell/Common/settings/SettingsSpec.js

@@ -185,6 +185,7 @@ var SPEC = {
     scrollTitleEnabled: { def: true },
     mediaAdaptiveWidthEnabled: { def: true },
     audioVisualizerEnabled: { def: true },
+    mediaUseAlbumArtAccent: { def: false },
     audioScrollMode: { def: "volume" },
     audioWheelScrollAmount: { def: 5 },
     audioDeviceScrollVolumeEnabled: { def: false },

quickshell/Modules/Settings/MediaPlayerTab.qml

@@ -65,6 +65,13 @@ Item {
                     onToggled: checked => SettingsData.set("mediaAdaptiveWidthEnabled", checked)
                 }
 
+                SettingsToggleRow {
+                    text: I18n.tr("Use album art accent")
+                    description: I18n.tr("Use colors extracted from album art instead of system theme colors")
+                    checked: SettingsData.mediaUseAlbumArtAccent
+                    onToggled: checked => SettingsData.set("mediaUseAlbumArtAccent", checked)
+                }
+
                 SettingsDropdownRow {
                     property var scrollOptsInternal: ["volume", "song", "nothing"]
                     property var scrollOptsDisplay: [I18n.tr("Change Volume", "media scroll wheel option"), I18n.tr("Change Song", "media scroll wheel option"), I18n.tr("Nothing", "media scroll wheel option")]

quickshell/Services/MediaAccentService.qml

@@ -11,14 +11,13 @@ import qs.Services
 Singleton {
     id: root
 
-    readonly property bool hasAccent: _accent !== null
-    readonly property color accent: _accent !== null ? _accent : Theme.primary
+    readonly property bool hasAccent: SettingsData.mediaUseAlbumArtAccent ? _accent !== null : true
+    readonly property color accent: SettingsData.mediaUseAlbumArtAccent && _accent !== null ? _accent : Theme.primary
 
-    readonly property color onAccent: {
-        const c = accent;
-        const lum = 0.2126 * c.r + 0.7152 * c.g + 0.0722 * c.b;
+    readonly property color onAccent: SettingsData.mediaUseAlbumArtAccent && _accent !== null ? (() => {
+        const lum = 0.2126 * _accent.r + 0.7152 * _accent.g + 0.0722 * _accent.b;
         return lum > 0.6 ? Qt.rgba(0, 0, 0, 1) : Qt.rgba(1, 1, 1, 1);
-    }
+    })() : Theme.onPrimary
 
     readonly property color accentHover: Theme.withAlpha(accent, 0.12)
     readonly property color accentPressed: Theme.withAlpha(accent, Theme.transparentBlurLayers ? 0.24 : 0.16)