Move the S256 verifier/challenge pair, the loopback callback handler, the bind-first
listener and the serve-until-redirect loop out of auth_spotify into auth_device_flow so a
second loopback PKCE provider does not copy 80 lines of HTTP-server plumbing. Spotify's
behaviour and error codes are unchanged; only its private copies are deleted.
* refactor(auth): one sign-in flow behind SignInState, rendered by the CLI and the desktop
* feat(gateway): /signin signs the free tier into a Nous account from a DM
* feat(cli): chat surfaces name /signin as the sign-in verb
* fix(auth): review follow-ups for the shared sign-in flow and /signin
* fix(i18n): carry the /status free-tier line in every locale catalog
* refactor(cli): the chat sign-in command is /login
* fix(auth): durable override cleanup in the /login sweep, and the sign-in flow in its own modules
For each issue anchor present in BASE 63279301bc non-test .py and absent on HEAD, the BASE comment/docstring block was re-attached at the HEAD location of the code it explained (matched by the distinctive code line / enclosing def). Sentences already covered by an existing HEAD comment were deduped; the issue number always survives. Insert-only: no code lines changed.
Teknium