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.

README.md

@@ -241,6 +241,21 @@ rm -f file.txt  # Falls through to standard rm -f
 | `upgrade` | Full system upgrade: `paru -Syu --noconfirm` |
 | `cleanup` | Log and remove orphaned packages |
 
+### Dependency Management
+
+`fish-deps` is a unified command for checking, installing, and updating all tools this config depends on.
+
+| Command | Description |
+|---|---|
+| `fish-deps` / `fish-deps status` | Show installed/missing status for all deps, grouped by tier |
+| `fish-deps install` | Interactively install each missing dep (prompts per-dep, prompts method when multiple exist) |
+| `fish-deps update` | Update all installed deps using their preferred install method |
+| `fish-deps sync` | Install missing deps then update installed ones |
+| `fzf-update` | Install or upgrade fzf from git HEAD into `~/.fzf` (guarantees the latest build) |
+| `check_fish_deps` | Legacy alias — delegates to `fish-deps status` |
+
+Install method priority: **cargo** (for Rust tools, gets latest crate) → **system PM** (paru/apt/brew/etc.) → **git clone** (fzf) → **curl installer** (starship, fisher) → **pipx** (Python tools). When multiple methods are available for a tool, you are prompted to choose.
+
 ### Docker
 
 | Function | Description |