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: ee6f7b4 (introduced MediaAccentService & ColorQuantizer)
       d799175 (tweaked seekbar accent colours)
       a62ae33 (further integrated accent into player/album art)
       c44ffae (monochrome art edge case fixes)

Author: hthienloc

quickshell/Services/MediaAccentService.qml

@@ -6,106 +6,17 @@ import QtQuick
 import qs.Common
 import qs.Services
 
-// Accent color extracted from the current track's album art via ColorQuantizer,
-// falling back to Theme.primary when no usable accent is available.
 Singleton {
     id: root
 
-    readonly property bool hasAccent: _accent !== null
-    readonly property color accent: _accent !== null ? _accent : Theme.primary
+    readonly property bool hasAccent: true
+    readonly property color accent: Theme.primary
 
-    readonly property color onAccent: {
-        const c = accent;
-        const lum = 0.2126 * c.r + 0.7152 * c.g + 0.0722 * c.b;
-        return lum > 0.6 ? Qt.rgba(0, 0, 0, 1) : Qt.rgba(1, 1, 1, 1);
-    }
+    readonly property color onAccent: Theme.onPrimary
 
     readonly property color accentHover: Theme.withAlpha(accent, 0.12)
     readonly property color accentPressed: Theme.withAlpha(accent, Theme.transparentBlurLayers ? 0.24 : 0.16)
 
     readonly property color accentTrack: Theme.withAlpha(accent, 0.28)
     readonly property color accentSubtle: Theme.withAlpha(accent, 0.55)
-
-    // Prefer the validated url, but fall back to the live mpris art so quantization
-    // starts as soon as the cover exists instead of waiting on the commit pipeline.
-    readonly property string artUrl: {
-        const resolved = TrackArtService.resolvedArtUrl;
-        if (resolved !== "")
-            return resolved;
-        const p = MprisController.activePlayer;
-        if (!p)
-            return "";
-        if (p.trackArtUrl)
-            return p.trackArtUrl;
-        const m = p.metadata;
-        return m && m["mpris:artUrl"] ? m["mpris:artUrl"].toString() : "";
-    }
-
-    // Hold the last accent across the brief artUrl blank between tracks; never reset to primary.
-    property var _accent: null
-
-    ColorQuantizer {
-        id: quantizer
-        source: root.artUrl
-        depth: 4
-        rescaleSize: 64
-        onColorsChanged: {
-            // Hold last accent only across the blank-art gap; else always recompute.
-            if (!colors || colors.length === 0)
-                return;
-            root._accent = root._pickAccent(colors);
-        }
-    }
-
-    function _pickAccent(colors) {
-        if (!colors || colors.length === 0)
-            return null;
-
-        let best = null;
-        let bestScore = -1;
-        for (let i = 0; i < colors.length; i++) {
-            const c = colors[i];
-            const s = c.hsvSaturation;
-            const v = c.hsvValue;
-            if (v < 0.22 || v > 0.96 || s < 0.22)
-                continue;
-            const score = s * (1 - Math.abs(v - 0.68));
-            if (score > bestScore) {
-                bestScore = score;
-                best = c;
-            }
-        }
-
-        if (best)
-            return _normalize(best);
-
-        // Monochrome art: pick a neutral tone instead of keeping the last accent.
-        return _pickNeutral(colors);
-    }
-
-    function _pickNeutral(colors) {
-        let best = null;
-        let bestScore = -1;
-        for (let i = 0; i < colors.length; i++) {
-            const c = colors[i];
-            const v = c.hsvValue;
-            const score = (1 - Math.abs(v - 0.6)) + c.hsvSaturation * 0.5;
-            if (score > bestScore) {
-                bestScore = score;
-                best = c;
-            }
-        }
-
-        const hue = best.hsvHue < 0 ? 0 : best.hsvHue;
-        const s = Math.min(best.hsvSaturation, 0.18);
-        const v = Math.min(Math.max(best.hsvValue, 0.6), 0.82);
-        return Qt.hsva(hue, s, v, 1);
-    }
-
-    function _normalize(c) {
-        const hue = c.hsvHue < 0 ? 0 : c.hsvHue;
-        const s = Math.min(1, c.hsvSaturation * 1.05);
-        const v = Math.max(c.hsvValue, 0.62);
-        return Qt.hsva(hue, s, v, 1);
-    }
 }