fix(diarization-ui): download markdown with sanitized document title filename

app.py

@@ -308,7 +308,16 @@ def download_md(doc_id: int):
         d = c.execute("SELECT title,content_md FROM documents WHERE id=?", (doc_id,)).fetchone()
     if not d:
         raise HTTPException(404, "not found")
-    return PlainTextResponse(d["content_md"], headers={"Content-Disposition": f"attachment; filename=document_{doc_id}.md"})
+
+    base = (d["title"] or f"document_{doc_id}").strip()
+    safe = "".join(ch if ch.isalnum() or ch in ("-", "_", " ") else "_" for ch in base).strip()
+    safe = safe.replace(" ", "_") or f"document_{doc_id}"
+    filename = f"{safe}.md"
+
+    return PlainTextResponse(
+        d["content_md"],
+        headers={"Content-Disposition": f"attachment; filename={filename}"},
+    )
 
 
 @app.post("/document/{doc_id}/rename", response_class=HTMLResponse)