fix(convert): auto-load default template for md-to-docx

Remove the hard-coded `template != \"default\"` guard so that
the default reference docx template is loaded automatically
when no --reference-doc is explicitly provided.

bin/commands/convert.py

@@ -96,7 +96,7 @@ def convert_cmd(inputs, output, template, quality, density, reference_doc, bookm
     # --- md → docx ---
     if all(p.suffix.lower() == ".md" for p in input_paths) and out_ext == ".docx":
         ref_doc = reference_doc
-        if not ref_doc and template != "default":
+        if not ref_doc:
             ref_path = templates_registry.get_md_to_docx_root() / template / "template.docx"
             if ref_path.exists():
                 ref_doc = str(ref_path)