feat: file manager — yazi (flagship TUI) + Thunar (GUI)

Legacy shipped only Thunar (and a stray nautilus extension, mid-migration).
This pairs a keyboard-driven TUI flagship that fits the distro's identity
with the GUI half for point-and-click + the "open folder" handler.

yazi (modules/home/yazi.nix, nomarchy.yazi.enable, SUPER+E, `y` shell
wrapper cd's on exit): themed from theme-state.json (mgr/mode/status
mapped from the palette; merges over yazi's defaults so it tracks the
theme) with a curated, correctly-wired plugin set —
  full-border, git (setup + prepend_fetchers), smart-enter (l/Enter),
  chmod (cm), mount (M), compress (caa), mediainfo (audio/subtitle only —
  images/videos keep native thumbnails), glow (markdown previews).
Preview/tooling deps: ffmpegthumbnailer, poppler-utils, p7zip, jq, fd,
ripgrep, fzf, chafa, mediainfo, glow.

Thunar (modules/nixos/file-manager.nix, nomarchy.system.fileManager.enable):
GTK file manager (Stylix-themed) + archive/volman/media-tags plugins +
gvfs/tumbler/udisks2 backends + thumbnailers + exo. udisks2 also backs
yazi's mount plugin.

Verified: flake check green, HM generation builds (yazi TOML/init.lua
render, all 8 plugins resolve), every package present in the live ISO
closure (offline install draws from it — no source-build leak).
Not verified: yazi's runtime preview/plugin behaviour needs a real
session (TUI; can't drive in CI here).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

README.md

@@ -45,7 +45,9 @@ Flat on purpose. Two module trees, one options file each, no hidden layers.
 ├── modules/
 │   ├── nixos/                     # the distro, system side
 │   │   ├── default.nix            #   Hyprland session, Pipewire, greetd, fonts
-│   │   └── options.nix            #   nomarchy.system.* toggles
+│   │   ├── options.nix            #   nomarchy.system.* toggles
+│   │   ├── plymouth.nix           #   boot splash, tinted from the JSON
+│   │   └── file-manager.nix       #   Thunar GUI + gvfs/tumbler/udisks2
 │   └── home/                      # the distro, user side
 │       ├── default.nix            #   entry point
 │       ├── options.nix            #   nomarchy.* option surface
@@ -57,7 +59,8 @@ Flat on purpose. Two module trees, one options file each, no hidden layers.
 │       ├── btop.nix
 │       ├── fuzzel.nix             #   launcher + nomarchy-menu (power, clip)
 │       ├── swaync.nix             #   notifications, same JSON
-│       └── idle.nix               #   hyprlock + hypridle, same JSON
+│       ├── idle.nix               #   hyprlock + hypridle, same JSON
+│       └── yazi.nix               #   flagship TUI file manager + plugins
 ├── hosts/
 │   ├── default/                   # reference machine (thin: boot, user, hostname)
 │   └── live.nix                   # bootable live ISO (try the distro, no install)
@@ -172,11 +175,13 @@ examples: **[docs/OVERRIDES.md](docs/OVERRIDES.md)**.
 | `nomarchy.fuzzel.enable` | `true` | Themed fuzzel + `nomarchy-menu` (power menu) |
 | `nomarchy.swaync.enable` | `true` | swaync notifications, themed |
 | `nomarchy.idle.enable` | `true` | hyprlock + hypridle (idle lock 5 min, display off 10, suspend 30) |
+| `nomarchy.yazi.enable` | `true` | yazi TUI file manager, themed + curated plugins |
 | `nomarchy.ghostty.enable` | `true` | Nomarchy's Ghostty |
 | `nomarchy.btop.enable` | `true` | btop with per-theme colors |
 | `nomarchy.stylix.enable` | `true` | GTK/Qt/cursor theming |
 | `nomarchy.themesDir` | Nomarchy's `themes/` | Where per-theme app overrides are probed |
 | `nomarchy.system.plymouth.enable` | `true` | Branded boot splash, background from the theme JSON (recolors on system rebuilds) |
+| `nomarchy.system.fileManager.enable` | `true` | Thunar GUI + gvfs/tumbler/udisks2 (the "open folder" handler) |
 | `nomarchy.system.greeter.enable` | `true` | greetd/tuigreet |
 | `nomarchy.system.audio.enable` | `true` | Pipewire stack |
 | `nomarchy.system.bluetooth.enable` | `true` | Bluetooth + blueman |
@@ -241,7 +246,8 @@ home-update                            # rebuild just the desktop layer
 
 Keybinds: `SUPER+Return` terminal · `SUPER+D` launcher · `SUPER+T` theme
 picker · `SUPER+SHIFT+T` next wallpaper · `SUPER+X` power menu ·
-`SUPER+N` notifications · `SUPER+CTRL+V` clipboard history · `SUPER+Q`
+`SUPER+E` file manager (yazi) · `SUPER+N` notifications · `SUPER+CTRL+V`
+clipboard history · `SUPER+Q`
 close · `SUPER+1..9` workspaces · `Print` region screenshot.
 
 ## 6. Extending