NoCredentialsConfiguredError

Raised when no credentials are configured for any default-resolvable provider.

Distinct from MissingCredentialsError (which targets a specific provider the user has selected): this fires from _get_default_model_spec() when auto-detection finds no usable credentials at all. Callers (the deferred- start path in the TUI and CLI) isinstance-check this type to recover by launching the TUI with model creation deferred, rather than string-matching the formatted message.