sessions: the node can act for an account with an app password. --account-credentials (SP_ACCOUNT_CREDENTIALS), a JSON object of DID to app password: for each, the node logs in at the account's PDS with com.atproto.server.createSession and uses that session wherever it writes to the account's repo: starting, updating and ending livestream records, the teleport and idle-finalize record updates, publishing videos and their tracks, and acting for the account's delegated moderators. For a network whose OAuth is unavailable, where the streamer cannot sign in to the node at all. One session per account, cached for an hour and made again on demand (the director's dev-credentials path logged in on every write); every server-side write path now takes its client from one place, statedb.UserXrpcClient, which prefers these credentials and otherwise uses the stored OAuth session as before. --dev-account-creds still works and feeds the same map