fix(deps): demote cargo/starship to rec, remove fisher from catalog

Required tier is now fish, fzf, and zoxide only — the tools the config
meaningfully can't function without. Everything else degrades gracefully.

- cargo: only used by fish-deps to install Rust tools or build fish from
  source; all paths are already gated on type -q cargo
- starship: type -q guard in conf.d/starship.fish; shell falls back to
  fish's built-in prompt without it
- fisher: auto-bootstrapped by first_run.fish; no need for users or
  fish-deps to manage it. Remove from catalog and clean up the now-dead
  fisher-bootstrap/special-fisher installer cases.

Catalog arrays verified aligned at 26 entries each.

functions/_fish_deps_install.fish

@@ -92,9 +92,6 @@ function _fish_deps_install
                 case fzf-update
                     set -a methods special-fzf
                     set -a method_labels "git clone (~/.fzf)"
-                case fisher-bootstrap
-                    set -a methods special-fisher
-                    set -a method_labels "curl bootstrap (fisher)"
                 case curl-installer
                     set -a methods special-curl
                     set -a method_labels "curl installer"
@@ -202,9 +199,6 @@ function _fish_deps_install
                     rm -rf "$_tmpdir"
                 case special-fzf
                     fzf-update
-                case special-fisher
-                    curl -sL https://raw.githubusercontent.com/jorgebucaran/fisher/main/functions/fisher.fish | source
-                    fisher update
                 case special-curl
                     if test "$bin" = starship
                         curl -sS https://starship.rs/install.sh | sh