refactor(interop): move PATH interop config to interop.nix

The environment setup for Windows PATH interop logically belongs in
interop.nix alongside the includePath option, rather than being buried
in the native systemd module.

Author: reasonableperson

modules/interop.nix

@@ -1,4 +1,4 @@
-{ lib, config, ... }:
+{ lib, pkgs, config, ... }:
 
 with builtins; with lib;
 {
@@ -32,6 +32,23 @@ with builtins; with lib;
         };
       };
 
+      environment = mkIf cfg.includePath {
+        # Capture Windows interop paths from the PATH set by WSL. Skip paths
+        # which don't start with /mnt/c; they are generic defaults (eg.
+        # /usr/local/sbin) that don't exist on NixOS.
+        variables.INTEROP_PATH = ''
+          $(echo -n "$PATH" \
+          | ${pkgs.coreutils}/bin/tr ':' '\n' \
+          | ${pkgs.gnugrep}/bin/grep '^${config.wsl.wslConf.automount.root}/' \
+          | ${pkgs.coreutils}/bin/paste -sd: -)
+        '';
+
+        extraInit = ''
+          export PATH="$PATH:$INTEROP_PATH"
+          unset INTEROP_PATH
+        '';
+      };
+
       warnings =
         let
           registrations = config.boot.binfmt.registrations;

modules/systemd/native/default.nix

@@ -57,22 +57,6 @@ with lib; {
         '';
       };
 
-      environment = lib.mkIf cfg.interop.includePath {
-        # Capture Windows interop paths from the PATH set by WSL. Skip paths
-        # which don't start with /mnt/c; they are generic defaults (eg.
-        # /usr/local/sbin) that don't exist on NixOS.
-        variables.INTEROP_PATH = ''
-          $(echo -n "$PATH" \
-          | ${pkgs.coreutils}/bin/tr ':' '\n' \
-          | ${pkgs.gnugrep}/bin/grep '^${cfg.wslConf.automount.root}/' \
-          | ${pkgs.coreutils}/bin/paste -sd: -)
-        '';
-
-        extraInit = ''
-          export PATH="$PATH:$INTEROP_PATH"
-          unset INTEROP_PATH
-        '';
-      };
     };
 
 }