fix(auto-pull): respect $__fish_user_dots_path for registry location

Both the auto-pull function and the PWD event handler hardcoded
$XDG_CONFIG_HOME/.user-dots/fish as the registry directory. They now
resolve $__fish_user_dots_path first, falling back to the same default,
so a custom path set via config-settings is honoured.

conf.d/auto-pull.fish

@@ -26,8 +26,8 @@ __fish_config_op_enabled __fish_config_op_autoexec; or exit
 #   repository entry rather than on every sub-directory change.
 function __auto_pull_on_pwd --on-variable PWD
     set -q __fish_config_dir; or set -g __fish_config_dir $XDG_CONFIG_HOME/fish
-
-    set -l list "$XDG_CONFIG_HOME/.user-dots/fish/auto-pull.list"
+    set -q __fish_user_dots_path; or set -l __fish_user_dots_path "$XDG_CONFIG_HOME/.user-dots/fish"
+    set -l list "$__fish_user_dots_path/auto-pull.list"
 
     # Candidate roots: the fish-config repo plus the user's registry.
     set -l roots $__fish_config_dir