The downloader already handles servers that return 200 to a Range
request by falling through to a truncating File::create on the .part
path, discarding stale partial bytes. That branch had no dedicated
fixture test — the SHA mismatch and Range-honouring resume cases were
covered but the mirror / proxy that strips Range support was not.
Adds spawn_no_range_server (always 200, full body regardless of Range
header) and download_file_restarts_when_server_ignores_range. Writes 12
bytes of stale content to .part, kicks off a download, asserts the
final file matches the fresh body exactly (not stale-bytes-prefixed)
and the .part file is cleaned up.
Brings the transcription downloader to test-coverage parity with
crates/llm/src/model_manager.rs per brief item #8 ("test coverage
parity" acceptance).
Jake
2371e73f18