add directory normalization

src/zona/builder.py

@@ -44,7 +44,15 @@ def discover(root: Path, out_dir: Path) -> list[Item]:
                 item.metadata, item.content = split_metadata(path)
                 item.type = ItemType.MARKDOWN
                 item.copy = False
-                item.destination = destination.with_suffix(".html")
+                name = destination.stem
+                if name == "index":
+                    item.destination = item.destination.with_suffix(".html")
+                else:
+                    relative = path.relative_to(base).with_suffix("")
+                    name = relative.stem
+                    item.destination = (
+                        out_dir / relative.parent / name / "index.html"
+                    )
             items.append(item)
     return items