chore: replace OpacityMask with MultiEffect Mask

MultiEffect used to do a hard cutoff and not work with soft masks, but
since Qt 6.10 (or 6.11) it works correctly, so we don't need the custom
mask anymore

assets/shaders/fade.frag

@@ -1,26 +0,0 @@
-#version 440
-
-layout(location = 0) in vec2 qt_TexCoord0;
-layout(location = 0) out vec4 fragColor;
-
-layout(std140, binding = 0) uniform buf {
-    mat4 qt_Matrix;
-    float qt_Opacity;
-    float fadeMargin;
-};
-
-layout(binding = 1) uniform sampler2D source;
-
-void main() {
-    vec4 tex = texture(source, qt_TexCoord0);
-    float factor = 1.0;
-    float margin = 0.1;
-
-    if (qt_TexCoord0.y < margin) {
-        factor = qt_TexCoord0.y / margin;
-    } else if (qt_TexCoord0.y > (1.0 - margin)) {
-        factor = (1.0 - qt_TexCoord0.y) / margin;
-    }
-
-    fragColor = tex * factor * qt_Opacity;
-}

assets/shaders/opacitymask.frag

@@ -1,19 +0,0 @@
-#version 440
-
-layout(location = 0) in vec2 qt_TexCoord0;
-layout(location = 0) out vec4 fragColor;
-
-layout(std140, binding = 0) uniform buf {
-    // qt_Matrix and qt_Opacity must always be both present
-    // if the built-in vertex shader is used.
-    mat4 qt_Matrix;
-    float qt_Opacity;
-};
-
-layout(binding = 1) uniform sampler2D source;
-layout(binding = 2) uniform sampler2D maskSource;
-
-void main()
-{
-    fragColor = texture(source, qt_TexCoord0.st) * (texture(maskSource, qt_TexCoord0.st).a) * qt_Opacity;
-}

components/effects/OpacityMask.qml

@@ -1,9 +0,0 @@
-import QtQuick
-import Quickshell
-
-ShaderEffect {
-    required property Item source
-    required property Item maskSource
-
-    fragmentShader: Quickshell.shellPath("assets/shaders/opacitymask.frag.qsb")
-}

modules/bar/components/workspaces/SpecialWorkspaces.qml

@@ -18,7 +18,7 @@ Item {
     readonly property string activeSpecial: (GlobalConfig.bar.workspaces.perMonitorWorkspaces ? monitor : Hypr.focusedMonitor)?.lastIpcObject.specialWorkspace?.name ?? ""
 
     layer.enabled: true
-    layer.effect: OpacityMask {
+    layer.effect: Mask {
         maskSource: mask
     }
 

modules/lock/Media.qml

@@ -31,7 +31,7 @@ Item {
         }
 
         layer.enabled: true
-        layer.effect: OpacityMask {
+        layer.effect: Mask {
             maskSource: mask
         }
 

modules/sidebar/NotifActionList.qml

@@ -20,7 +20,7 @@ Item {
 
     layer.enabled: true
     layer.smooth: true
-    layer.effect: OpacityMask {
+    layer.effect: Mask {
         maskSource: gradientMask
     }