End-to-end proof of the whole sharing stack with no mock peer: a sharer indexes a temp file, the leecher's search is distributed by soulfind, the sharer replies with a FileSearchResponse, and the leecher downloads the real bytes that the sharer serves over a peer-to-peer transfer. Asserts the search result and that the downloaded bytes match the source. Server-gated (SOULSEEK_E2E_REQUIRED).