Searches: grep was potentially matching nested IDs from search result
objects. Switch to splitting JSON at { boundaries and requiring
"searchText" presence — only top-level search objects have that field.
Transfers: DELETE /api/v0/transfers/downloads/{username} returns 405
(endpoint does not exist). Replace with per-user GET then per-file
DELETE /api/v0/transfers/downloads/{username}/{id}, using the same
{-split + state grep approach to extract terminal-state file IDs.