feat(home): add pandoc with texlive for PDF output

texlive scheme is the `local.texlive.package` option (default scheme-medium)
so consumers can swap schemes without editing the module; TEXMF* vars keep
its cache/config out of $HOME. pandoc PDF defaults to xelatex — pdflatex
fails on combining Unicode (e.g. U+0308 in decomposed ä).

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

modules/home.nix

@@ -71,7 +71,7 @@ let
   '';
 in
 {
-  imports = [ ./gpg.nix ./media.nix ];
+  imports = [ ./gpg.nix ./media.nix ./texlive.nix ];
 
   # Put ~/.local/bin (the XDG user-bin dir) on PATH so hand-dropped scripts run
   # by name without wiring each through nix.
@@ -185,6 +185,14 @@ in
 
   programs.home-manager.enable = true;
 
+  # Document converter (md/html/docx/…). PDF output shells out to a LaTeX engine
+  # (texlive.nix): default it to xelatex, which is Unicode-native — pdflatex
+  # (pandoc's own default) fails on combining marks, e.g. U+0308 in decomposed ä.
+  programs.pandoc = {
+    enable = true;
+    defaults.pdf-engine = "xelatex";
+  };
+
   programs.git = {
     enable = true;
     settings = {