refactor(nixos): remove unused direnv module

configs/nixos/modules/shell/direnv/default.nix

@@ -1,25 +0,0 @@
-{
-  config,
-  lib,
-  ...
-}:
-# direnv for the primary user, configured through home-manager.
-let
-  user = config.user.name;
-in
-{
-  options.modules.shell.direnv.enable =
-    lib.mkEnableOption "direnv for the primary user, with nix-direnv shell caching";
-
-  config = lib.mkIf config.modules.shell.direnv.enable {
-    home-manager.users.${user}.programs.direnv = {
-      enable = true;
-      silent = true;
-
-      # nix-direnv caches the evaluated shell so re-entering a directory is instant
-      # instead of re-running `nix develop`, and adds the `use flake` stdlib helper.
-      nix-direnv.enable = true;
-      stdlib = builtins.readFile ./repo-flake.sh;
-    };
-  };
-}

configs/nixos/modules/shell/direnv/repo-flake.sh

@@ -1,33 +0,0 @@
-if declare -f use_flake >/dev/null; then
-  __dotfiles_use_flake_definition="$(declare -f use_flake)"
-  eval "${__dotfiles_use_flake_definition/use_flake/__dotfiles_nix_direnv_use_flake}"
-  unset __dotfiles_use_flake_definition
-
-  use_flake() {
-    local flake_expr="${1:-.}"
-
-    if [[ "$flake_expr" == //* ]]; then
-      local git_root
-      if ! git_root="$(git rev-parse --show-toplevel 2>/dev/null)"; then
-        log_error 'use flake // requires a Git repository'
-        return 1
-      fi
-
-      local flake_suffix="${flake_expr#//}"
-      if [[ -n "$flake_suffix" && "$flake_suffix" != \#* && "$flake_suffix" != /* ]]; then
-        flake_expr="path:${git_root}/${flake_suffix}"
-      else
-        flake_expr="path:${git_root}${flake_suffix}"
-      fi
-
-      shift
-      __dotfiles_nix_direnv_use_flake "$flake_expr" "$@"
-      return
-    fi
-
-    __dotfiles_nix_direnv_use_flake "$@"
-  }
-else
-  log_error 'nix-direnv must define use_flake before the // wrapper loads'
-  return 1
-fi