The remote-dl client sends exact_lang in dl_params, and REST download jobs set it in the service ctx, so a service can skip the manifests of close-match languages.
A REST job shows a wait_for_approval message as its notice field. search, list-titles and list-tracks fail at once on a login that needs the user. A remote client downloads through the --proxy it sends.
Failed jobs now keep the worker's traceback, error_details and error_code instead of the "Worker exited" wrapper. error_traceback and worker_stderr only reach API clients under --debug-api.
Remote sessions now carry -l/-vl/-al/-a/-fs under a nested dl_params, so services fetch the requested audio versions. Server-account tokens for non-default accounts move from default to the account name, so each account logs in once after upgrade.
Covers RemoteClient/RemoteService, REST routes, handlers, SessionStore, InputBridge, DownloadQueueManager, errors, compression, and serve CLI. E2e tier opts in via --live and can auto-spawn its own serve.