Builds the Redaction engine for one protocol vocabulary. The
mechanism is owned here; the vocabulary is the caller's — the
consuming SDK passes every key that names a credential on ITS wire,
and the engine unions them with BASE_SENSITIVE_KEYS.
Parameters
extraSensitiveKeys: Iterable<string> = []
Protocol-specific credential keys, in any
casing, added on top of the base vocabulary.
Builds the Redaction engine for one protocol vocabulary. The mechanism is owned here; the vocabulary is the caller's — the consuming SDK passes every key that names a credential on ITS wire, and the engine unions them with BASE_SENSITIVE_KEYS.