feat: restructure R2 key to namespace/uid/timestamp-rand format

r2_uploader.py

@@ -2,7 +2,7 @@
 
 Reads R2 credentials from the ``SCONFIG`` Space secret (a JSON blob) and uploads
 generated assets to a preset bucket. Object keys follow
-``<yyyymmddhhmmss>-<namespace>-<rand>.<ext>``; the prompt and request params are
+``<namespace>/<uid>/<yyyymmddhhmmss>-<rand>.<ext>``; the prompt and request params are
 attached as JSON object metadata so the owner can trace any asset back to the
 request that produced it.
 
@@ -255,7 +255,8 @@ def upload_asset(
             with open(path, "rb") as fh:
                 data = fh.read()
 
-        filekey = f"{_now_stamp()}-{namespace}-{uuid.uuid4().hex[:8]}{ext}"
+        safe_uid = uid or "anonymous"
+        filekey = f"{namespace}/{safe_uid}/{_now_stamp()}-{uuid.uuid4().hex[:8]}{ext}"
 
         s3 = _client(cfg)
         _ensure_bucket(s3, bucket)