[work] Fix conflict with salt

Configured nix-darwin to write shell configuration to .local
variants (/etc/bash.local, /etc/zshrc.local, /etc/zshenv.local) instead
of managing the main shell files. This allows Salt (corporate laptop
management) to manage /etc/bashrc, /etc/zshrc, and /etc/zshenv while
nix-darwin provides the Nix environment setup through the .local files
that Salt already sources.

roles/darwin.nix

@@ -1,9 +1,47 @@
-{ lib, pkgs, ... }:
+{ config, lib, pkgs, ... }:
 
 with lib;
 
+let
+  # Extract the set-environment path that nix-darwin generates
+  setEnvironmentPath = "${config.system.build.setEnvironment}";
+in
 {
   config = {
+    # Salt manages /etc/bashrc, /etc/zshrc, /etc/zshenv
+    # nix-darwin writes to .local variants for nix-specific configuration
+
+    # Disable nix-darwin from managing the main shell files
+    environment.etc."bashrc".enable = false;
+    environment.etc."zshrc".enable = false;
+    environment.etc."zshenv".enable = false;
+
+    # Create .local files with nix environment setup
+    environment.etc."bash.local".text = ''
+      # Nix environment setup
+      if [ -z "$__NIX_DARWIN_SET_ENVIRONMENT_DONE" ]; then
+        . ${setEnvironmentPath}
+      fi
+    '';
+
+    environment.etc."zshrc.local".text = ''
+      # Nix environment setup (already done in zshenv.local)
+    '';
+
+    environment.etc."zshenv.local".text = ''
+      # Nix environment setup
+      if [[ -o rcs ]]; then
+        if [ -z "''${__NIX_DARWIN_SET_ENVIRONMENT_DONE-}" ]; then
+          . ${setEnvironmentPath}
+        fi
+
+        # Tell zsh how to find installed completions
+        for p in ''${(z)NIX_PROFILES}; do
+          fpath=($p/share/zsh/site-functions $p/share/zsh/$ZSH_VERSION/functions $p/share/zsh/vendor-completions $fpath)
+        done
+      fi
+    '';
+
     time.timeZone = "America/Los_Angeles";
 
     environment.systemPackages = with pkgs; [