Add optional ONSALE_ROBLOSECURITY_TOKEN and ONSALE_PUBLISHER_USER_ID
env vars to use a different Roblox account for putting items on sale.
Falls back to the upload account when not set. Update README with
new config options and API endpoint docs.
- Replace hand-rolled roblox_service.py and models.py with rbx-upload
- Initialize RobloxClient in FastAPI lifespan context manager
- Remove leaked singleton httpx.AsyncClient
- Simplify upload_clothing_image call (group_id int instead of RbxCreator)
- Fix GET /asset/{id} returning a set literal instead of a dict
- Drop httpx direct dependency (now transitive via rbx-upload)
ivy