chore: move module/constants.nix to lib/default.nix

lib/colours/solarized-light.nix

@@ -0,0 +1,37 @@
+rec {
+  black = {
+    dark = "#073642";
+    bright = "#002b36";
+  };
+  red = {
+    dark = "#dc322f";
+    bright = "#cb4b16";
+  };
+  yellow = {
+    dark = "#b58900";
+    bright = "#657b83";
+  };
+  green = {
+    dark = "#859900";
+    bright = "#586e75";
+  };
+  blue = {
+    dark = "#268bd2";
+    bright = "#839496";
+  };
+  magenta = {
+    dark = "#d33682";
+    bright = "#6c71c4";
+  };
+  cyan = {
+    dark = "#2aa198";
+    bright = "#93a1a1";
+  };
+  white = {
+    dark = "#eee8d5";
+    bright = "#fdf6e3";
+  };
+  background = white.bright;
+  foreground = yellow.bright;
+  cursor = green.bright;
+}