feat: make AGS colorshell configuration fully declarative

- Add complete colorshell v2.0.3 configuration to home/ags-config/
- Disable runner plugin and NightLight tile (incompatible with NixOS)
- Customize SCSS with full opacity (no transparency)
- Add dark pale blue color scheme in home/pywal-colors/
- Configure Papirus-Dark icon theme via home-manager
- Make ~/.config/ags/ immutable and managed by Nix store
- Auto-deploy pywal colors to ~/.cache/wal/colors.json

All AGS configuration is now reproducible and version controlled.

home/ags-config/resources/styles/_float-notifications.scss

@@ -0,0 +1,18 @@
+@use "./colors";
+@use "./mixins";
+
+.floating-notifications-container {
+  padding: 16px;
+
+  & .float-notification {
+    $radius: 18px;
+
+    box-shadow: 0 0 8px 1px colors.$bg-translucent;
+    border-radius: $radius;
+
+    & .notification {
+      padding: 4px;
+      border-radius: $radius;
+    }
+  }
+}