fix karaoke: lazy-load unsandbox SDK to avoid import failure in CI

make_post_sell/lib/karaoke.py

@@ -17,9 +17,16 @@ from concurrent.futures import ThreadPoolExecutor, as_completed
 
 log = logging.getLogger(__name__)
 
-# Use the unsandbox Python SDK for API requests
-sys.path.insert(0, os.path.expanduser("~/git/un-inception"))
-from un import _make_request, _resolve_credentials  # noqa: E402
+_un_loaded = False
+
+
+def _load_un():
+    global _un_loaded
+    if not _un_loaded:
+        sys.path.insert(0, os.path.expanduser("~/git/un-inception"))
+        _un_loaded = True
+    from un import _make_request, _resolve_credentials, validate_keys
+    return _make_request, _resolve_credentials, validate_keys
 
 VOXSPLIT_SOURCE = os.environ.get(
     "VOXSPLIT_SOURCE_PATH",
@@ -37,6 +44,7 @@ def process_karaoke(s3_client, bucket, s3_key, s3_path,
 
     Returns dict {"instrumentals": size, "vocals": size} on success, None on failure.
     """
+    _make_request, _resolve_credentials, _ = _load_un()  # lazy import
     public_key, secret_key = _resolve_credentials(public_key, secret_key)
 
     with tempfile.TemporaryDirectory(prefix="karaoke_") as tmpdir:
@@ -168,7 +176,7 @@ def backfill_karaoke_async(shop_id, session_factory, app_settings):
             from sqlalchemy.orm import Session as SASession
             from ..models.product import Product, get_media_type
             from ..models.shop import Shop
-            from un import validate_keys
+            _, _, validate_keys = _load_un()
 
             session = SASession(bind=session_factory().get_bind())