Seven calls each spelled out send, describe the transport error, map a 401, and
refuse anything else as unexpected_status; two read the server's {"error"} words
the same way. send_raw (transport + a 401 whose meaning the caller names), send
(and anything but success is unexpected) and server_reason now hold those steps.
Each call keeps only what is its own: device_login's and fetch_identity's 401
wording, the release's 404 = none, sharing's 404 and refusal reason, upload's
retry split.
DRY pass #2, batch 2, F6 (#5372).
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>