The declared rate budget for an operation (e.g. read off the document's x-suluk-ratelimit).
OptionalstoreThe durable counter (default: a per-instance MemoryRateLimitStore — DEV ONLY).
OptionalkeyDerive the caller key from a request + facet (default: client IP from x-forwarded-for / x-real-ip).
OptionalnowThe clock (default: Date.now) — the single source of now.
OptionaldefaultA blanket budget applied to operations that declare none (escape hatch; default: unmetered).
Resolve the contract operation for a request (undefined ⇒ a non-contract path, passed through).