8495cbaa24
Point $__fish_config_dir/user-dots at $__fish_user_dots_path on interactive startup so the private overlay can be browsed from the fish config dir. The link is created if missing and repointed if the path variable changes, only ever managing a symlink (never clobbering a real file/dir). Gated as a C2 startup side-effect (__fish_config_op_autoexec) and git-ignored. Docs: README overlay section and fish-config.md C2 table updated.