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/icons/loop-arrow-symbolic.svg

@@ -0,0 +1,2 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<svg xmlns="http://www.w3.org/2000/svg" height="16px" viewBox="0 0 16 16" width="16px"><g fill="#222222"><path d="m 4 3 c -2.199219 0 -4 1.800781 -4 4 v 2 c 0 2.199219 1.800781 4 4 4 c 0.550781 0 1 -0.449219 1 -1 s -0.449219 -1 -1 -1 c -1.125 0 -2 -0.875 -2 -2 v -2 c 0 -1.125 0.875 -2 2 -2 h 8 c 1.125 0 2 0.875 2 2 v 2 c 0 1.125 -0.875 2 -2 2 h -4 c -0.550781 0 -1 0.449219 -1 1 s 0.449219 1 1 1 h 4 c 2.199219 0 4 -1.800781 4 -4 v -2 c 0 -2.199219 -1.800781 -4 -4 -4 z m 0 0"/><path d="m 10 10.996094 v -2.003906 h -1 v 0.007812 c -0.265625 0 -0.519531 0.105469 -0.707031 0.289062 l -2 2 c -0.390625 0.390626 -0.390625 1.023438 0 1.414063 l 2 2 c 0.1875 0.183594 0.441406 0.289063 0.707031 0.285156 v 0.011719 h 1 v -1.992188"/></g></svg>