0.5.0

Added

• QTSurfer.auth(apikey) (plus auth() env-var overload and auth(apikey, AuthOptions)) — one-call helper that exchanges a long-lived API key for a short-lived JWT and returns an AuthenticatedClient. The returned session mirrors the existing QTSurfer surface (compile, backtest, exchanges, instruments, tickers, klines) but transparently refreshes the JWT once on a 401 before retrying.
• com.qtsurfer.api.sdk.auth.TokenStore interface (load / save / clear) and a default InMemoryTokenStore. Adopters can plug in a file, secret manager, or desktop keychain. AuthOptions is the configuration record (base URL, token store, HTTP client, executor) — defaults to https://api.qtsurfer.com/v1 and an in-memory store.
• QTSURFER_APIKEY environment variable: read by QTSurfer.auth(null, ...) / QTSurfer.auth() when no API key argument is passed.
• QTSAuthError (subclass of QTSError) raised when no API key is available or the JWT exchange fails.

Changed

• Bumped com.qtsurfer:api-client-java to 0.3.1 (adds AuthApi, AuthTokenResponse, AuthTokenError).
• DownloadFormat#wire() is now public so the auth-session can pass the underlying ExchangeBinaryDownloads.Format through.