feat(deps): add fish-deps unified dependency management command

Introduces `fish-deps` with four subcommands:
- status: colored installed/missing report per tier (required/integrations/recommended)
- install: interactively install each missing dep, prompts method when multiple exist
- update: update all installed deps using their preferred method
- sync: install missing then update installed

Install method priority: cargo (Rust tools get latest crate) > system PM
(paru/pacman/apt/brew/pkg/dnf/yum) > git clone (fzf via fzf-update) >
curl installer (starship, fisher) > pipx (wakatime).

Splits into focused helper files:
- _fish_deps_catalog.fish: parallel-array dep catalog with tiers, cargo crates, PM names, special install keys
- _fish_deps_pm.fish: PM detection and install/upgrade helpers
- _fish_deps_status.fish: tier-grouped colored status display
- _fish_deps_install.fish: per-dep interactive install with method selection
- _fish_deps_update.fish: per-dep update using known install method

check_fish_deps becomes a thin wrapper delegating to `fish-deps status`.
README updated with Dependency Management section.

functions/check_fish_deps.fish

@@ -1,50 +1,7 @@
 # Copyright (C) 2026 Rootiest
 # SPDX-License-Identifier: AGPL-3.0-or-later
 
-# Check all fish-related dependencies
+# Thin wrapper kept for backwards compatibility.
 function check_fish_deps --description 'Check all fish-related dependencies'
-    set -l required fish fisher starship fzf zoxide direnv paru
-    set -l integrations wakatime tailscale
-    set -l recommended eza lsd bat btop dust duf prettyping most rg lazygit lazydocker trash kitty wezterm
-
-    function __print_dep
-        set -l dep $argv[1]
-        if type -q $dep
-            set_color green
-            echo -n "   "
-            set_color normal
-            echo -n "$dep "
-            set_color brblack
-            echo "(Found at "(type -p $dep)")"
-            set_color normal
-        else
-            set_color red
-            echo -n "   "
-            set_color normal
-            echo -n "$dep "
-            set_color brblack
-            echo "(Not installed)"
-            set_color normal
-        end
-    end
-
-    set_color cyan; echo "Required Dependencies:"; set_color normal
-    for dep in $required
-        __print_dep $dep
-    end
-    echo ""
-
-    set_color cyan; echo "Integrations:"; set_color normal
-    for dep in $integrations
-        __print_dep $dep
-    end
-    echo ""
-
-    set_color cyan; echo "Recommended Dependencies:"; set_color normal
-    for dep in $recommended
-        __print_dep $dep
-    end
-    echo ""
-    
-    functions -e __print_dep
+    fish-deps status
 end