Add Noctalia shell with Quickshell overview

- Add `noctalia` input to flake and lock it in `flake.lock`.
- Include `noctalia` and `quickshell` modules in `flake.nix`.
- Extend core packages to accept `inputs` and `system`; add
  `quickshell.nix`
  with required Qt6 packages and environment variables.
- Enable `upower` service for battery handling.
- Add home modules `noctalia.nix` and `overview.nix` (QML UI, README,
  assets, widgets, services) to provide a workspace overview.
- Comment out unused rofi and web‑search binds; update `exec‑once` to
  start
  the overview daemon and `noctalia-shell`.
- Provide `restart.noctalia` script and its Nix wrapper.
- Enable `noctalia-shell` in `stylix` configuration.

modules/home/overview/common/functions/ColorUtils.qml

@@ -0,0 +1,68 @@
+pragma Singleton
+import Quickshell
+
+Singleton {
+    id: root
+
+    function colorWithHueOf(color1, color2) {
+        var c1 = Qt.color(color1);
+        var c2 = Qt.color(color2);
+        var hue = c2.hsvHue;
+        var sat = c1.hsvSaturation;
+        var val = c1.hsvValue;
+        var alpha = c1.a;
+        return Qt.hsva(hue, sat, val, alpha);
+    }
+
+    function colorWithSaturationOf(color1, color2) {
+        var c1 = Qt.color(color1);
+        var c2 = Qt.color(color2);
+        var hue = c1.hsvHue;
+        var sat = c2.hsvSaturation;
+        var val = c1.hsvValue;
+        var alpha = c1.a;
+        return Qt.hsva(hue, sat, val, alpha);
+    }
+
+    function colorWithLightness(color, lightness) {
+        var c = Qt.color(color);
+        return Qt.hsla(c.hslHue, c.hslSaturation, lightness, c.a);
+    }
+
+    function colorWithLightnessOf(color1, color2) {
+        var c2 = Qt.color(color2);
+        return colorWithLightness(color1, c2.hslLightness);
+    }
+
+    function adaptToAccent(color1, color2) {
+        var c1 = Qt.color(color1);
+        var c2 = Qt.color(color2);
+        var hue = c2.hslHue;
+        var sat = c2.hslSaturation;
+        var light = c1.hslLightness;
+        var alpha = c1.a;
+        return Qt.hsla(hue, sat, light, alpha);
+    }
+
+    function mix(color1, color2, percentage = 0.5) {
+        var c1 = Qt.color(color1);
+        var c2 = Qt.color(color2);
+        return Qt.rgba(
+            percentage * c1.r + (1 - percentage) * c2.r,
+            percentage * c1.g + (1 - percentage) * c2.g,
+            percentage * c1.b + (1 - percentage) * c2.b,
+            percentage * c1.a + (1 - percentage) * c2.a
+        );
+    }
+
+    function transparentize(color, percentage = 1) {
+        var c = Qt.color(color);
+        return Qt.rgba(c.r, c.g, c.b, c.a * (1 - percentage));
+    }
+
+    function applyAlpha(color, alpha) {
+        var c = Qt.color(color);
+        var a = Math.max(0, Math.min(1, alpha));
+        return Qt.rgba(c.r, c.g, c.b, a);
+    }
+}

modules/home/overview/common/functions/qmldir

@@ -0,0 +1 @@
+singleton ColorUtils 1.0 ColorUtils.qml