update

backend/paths.py

@@ -0,0 +1,17 @@
+from pathlib import Path
+
+from config import STORAGE_DIR
+
+
+def safe_basename(topic: str, format_name: str) -> str:
+    clean = topic.replace("/", "_").replace("\x00", "")
+    return f"{clean} - {format_name}"
+
+
+def final_paths(topic: str, format_name: str) -> tuple[Path, Path]:
+    base = safe_basename(topic, format_name)
+    return STORAGE_DIR / "html" / f"{base}.html", STORAGE_DIR / "pdf" / f"{base}.pdf"
+
+
+def temp_paths(guide_id: str) -> tuple[Path, Path]:
+    return STORAGE_DIR / "html" / f"{guide_id}.tmp.html", STORAGE_DIR / "pdf" / f"{guide_id}.tmp.pdf"