feat(docs): add auto-generated Markdown wiki

Adds docs/split-wiki.py, a Python script that splits fish-config.md
into a multi-page Markdown wiki under docs/wiki/:

- index.md: DESCRIPTION intro + full section ToC
- one file per numbered section (1-configuration-variables.md … 9-viewing-this-manual.md)
- each section page has a nav bar at the top linking to every other section

The build-docs.yml workflow now runs the script alongside pandoc so all
three formats (man page, HTML, wiki) are regenerated together from a
single source in one CI run.

README slimmed down to a pointer to the wiki; docs/fish-config.md §9
gains an "As a wiki" subsection.

docs/wiki/6-dependency-catalog.md

@@ -0,0 +1,56 @@
+# 6. DEPENDENCY CATALOG
+
+**Sections:** [Index](index.md) | [1. Configuration Variables](1-configuration-variables.md) | [2. Path Setup](2-path-setup.md) | [3. Key Bindings](3-key-bindings.md) | [4. Abbreviations](4-abbreviations.md) | [5. Functions Reference](5-functions-reference.md) | **6. Dependency Catalog** | [7. Customization](7-customization.md) | [8. Fisher Plugins](8-fisher-plugins.md) | [9. Viewing This Manual](9-viewing-this-manual.md)
+
+---
+
+fish-deps manages these tools. Run `fish-deps` to check status, or
+`fish-deps install` to install missing ones.
+
+## Required
+
+    uv        Python package manager (Astral)
+    cargo     Rust toolchain (via rustup)
+    fish      Fish shell >= 4.0
+    fisher    Fish plugin manager
+    starship  Cross-shell prompt
+    fzf       Fuzzy finder
+    zoxide    Smart cd with frecency
+    direnv    Per-directory environment loading
+    paru      AUR helper (Arch only; preferred)
+    yay       AUR helper (Arch only; fallback)
+
+## Integrations
+
+    wakatime   Developer time tracking
+    tailscale  Mesh VPN client
+
+## Recommended
+
+    eza         Modern ls replacement
+    lsd         ls replacement (fallback to eza)
+    bat         Syntax-highlighted cat
+    btop        Modern resource monitor
+    dust        Disk usage tree (Rust)
+    duf         Disk usage/free overview
+    prettyping  Colorized ping wrapper
+    ov          Modern pager (replaces less)
+    ripgrep     Fast line search
+    lazygit     Terminal git UI
+    lazydocker  Terminal docker UI
+    trash       Safe delete (trash-cli)
+    kitty       GPU-accelerated terminal (primary)
+    wezterm     GPU-accelerated terminal (alternative)
+
+## Install Methods
+
+The install priority for each tool:
+
+    cargo     Rust tools (eza, lsd, bat, dust, ov, ripgrep, trashy, zoxide,
+              starship) — always gets the latest crate version
+    system PM paru / apt / brew / dnf / etc. — for tools without a crate
+    git clone fzf — installed from GitHub to ~/.fzf/
+    curl      starship installer, fisher bootstrap, uv installer
+    pipx      Python-based tools
+
+---