fix: yazi fetcher group field, xfce package renames, enable nix-ld

Three quick known-issue fixes:

- yazi: 26.x made the fetcher `group` field required, so the git
  prepend_fetchers failed to parse and yazi fell back to presets. Add
  `group = "git"` to both entries (the git plugin's setup() only renders
  the linemode — the fetcher still needs registering here).
- file-manager: xfce.exo and the three Thunar plugins moved to top-level;
  use pkgs.xfce4-exo / pkgs.thunar-{archive-plugin,volman,media-tags-plugin}.
  Clears the eval-time deprecation warnings.
- nix-ld: enable programs.nix-ld distro-wide so foreign dynamically-linked
  binaries (downloaded tools, npx-fetched claude-code, language servers)
  run without patchelf.

Also drops the now-stale claude-code mention from the allowUnfree comment
(the ask module uses npx). nix flake check passes; xfce warnings gone.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

modules/home/yazi.nix

@@ -46,9 +46,12 @@ in
         };
         plugin = {
           # git status in the linemode (fetcher registered before setup).
+          # yazi 26.x made `group` required on fetchers (without it the
+          # config fails to parse and yazi falls back to presets); "*"
+          # matches files, "*/" dirs, so they share the "git" group.
           prepend_fetchers = [
-            { id = "git"; url = "*"; run = "git"; }
-            { id = "git"; url = "*/"; run = "git"; }
+            { id = "git"; url = "*"; run = "git"; group = "git"; }
+            { id = "git"; url = "*/"; run = "git"; group = "git"; }
           ];
           # Route only audio + subtitles to mediainfo's text metadata;
           # images/videos keep yazi's native visual thumbnails. Markdown