xdg: move config and cache to ~/.local

home-manager/fish.nix

···
             position = "anywhere";
             expansion = "--log-format internal-json -v 2&| nom --json";
           };
+          ".c/" = {
+            position = "anywhere";
+            setCursor = true;
+            expansion = "$XDG_CONFIG_HOME/%";
+          };
         };
       };
 

home-manager/xdg.nix

···
 {
+  flake.modules.nixos.core =
+    { config, ... }:
+    {
+      environment.sessionVariables = {
+        XDG_CONFIG_HOME = "$HOME/.local/config";
+        XDG_CACHE_HOME = "$HOME/.local/cache";
+      };
+    };
   flake.modules.homeManager.core =
     { config, pkgs, ... }:
     let
+      inherit (config.home) homeDirectory;
       inherit (config.xdg) dataHome stateHome;
     in
     {
+      xdg.configHome = "${homeDirectory}/.local/config";
+      xdg.cacheHome = "${homeDirectory}/.local/cache";
       xdg.userDirs = {
         enable = pkgs.stdenv.hostPlatform.isLinux;
-        desktop = "${config.home.homeDirectory}/desktop";
-        documents = "${config.home.homeDirectory}/documents";
-        download = "${config.home.homeDirectory}/downloads";
-        music = "${config.home.homeDirectory}/music";
-        pictures = "${config.home.homeDirectory}/pictures";
-        publicShare = "${config.home.homeDirectory}/public";
-        templates = "${config.home.homeDirectory}/templates";
-        videos = "${config.home.homeDirectory}/videos";
+        desktop = "${homeDirectory}/desktop";
+        documents = "${homeDirectory}/documents";
+        download = "${homeDirectory}/downloads";
+        music = "${homeDirectory}/music";
+        pictures = "${homeDirectory}/pictures";
+        publicShare = "${homeDirectory}/public";
+        templates = "${homeDirectory}/templates";
+        videos = "${homeDirectory}/videos";
       };
 
       home.preferXdgDirectories = true;
       home.sessionVariables = {
         CARGO_HOME = "${dataHome}/cargo";
-        CARGO_INSTALL_ROOT = "${config.home.homeDirectory}/.local";
+        CARGO_INSTALL_ROOT = "${homeDirectory}/.local";
         HISTFILE = "${stateHome}/bash/history";
         LESSHISTFILE = "${stateHome}/less/history";
       };