update

backend/paths.py

@@ -0,0 +1,16 @@
+from pathlib import Path
+
+from config import STORAGE_DIR, PROJECTS_DIR
+
+
+def safe_basename(topic: str, format_name: str) -> str:
+    clean = topic.replace("/", "_").replace("\x00", "")
+    return f"{clean} - {format_name}"
+
+
+def final_html_path(topic: str, format_name: str) -> Path:
+    return STORAGE_DIR / "html" / f"{safe_basename(topic, format_name)}.html"
+
+
+def project_dir(name: str) -> Path:
+    return PROJECTS_DIR / name