treewide: move everything to xdg

modules/home/common/default.nix

@@ -20,6 +20,7 @@ in
   imports = [
     ./desktop
     fishOverlayModule
+    ./xdg.nix
   ];
 
   programs.fish.enable = true;

modules/home/common/xdg.nix

@@ -0,0 +1,29 @@
+{ config, ... }:
+let
+  inherit (config.xdg)
+    dataHome
+    cacheHome
+    configHome
+    stateHome
+    ;
+in
+{
+  xdg.enable = true;
+
+  home.sessionVariables = {
+    SQLITE_HISTORY = "${cacheHome}/sqlite_history";
+    PSQL_HISTORY = "${dataHome}/psql_history";
+    NPM_CONFIG_USERCONFIG = "${configHome}/npm/npmrc";
+    NODE_REPL_HISTORY = "${dataHome}/node_repl_history";
+    LESSHISTFILE = "${stateHome}/less/history";
+    GRADLE_USER_HOME = "${dataHome}/gradle";
+    GEM_SPEC_CACHE = "${cacheHome}/gem";
+    GEM_HOME = "${dataHome}/gem";
+    CP_HOME_DIR = "${dataHome}/cocoapods";
+    CARGO_HOME = "${dataHome}/cargo";
+    W3M_DIR = "${dataHome}/w3m";
+    STACK_XDG = 1;
+  };
+
+  # TODO: Manage npmrc with nix too
+}

modules/system/settei/sane-defaults.nix

@@ -57,6 +57,7 @@ let
             "auto-allocate-uids"
           ];
           trusted-users = lib.optionals (!adminNeedsPassword) [ username ];
+          use-xdg-base-directories = true;
           auto-allocate-uids = true;
           extra-substituters = [
             "https://hyprland.cachix.org"