Function resolve_usage 

pub fn resolve_usage(
    cache: Option<&CacheStore>,
    lock: Option<&LockStore>,
    transport: &dyn UsageTransport,
    credentials: &dyn Fn() -> Arc<Result<Credentials, CredentialError>>,
    jsonl: &dyn Fn() -> Result<JsonlAggregate, JsonlError>,
    now: &dyn Fn() -> Timestamp,
    config: &UsageCascadeConfig,
) -> Result<UsageData, UsageError>

Resolve OAuth usage data using the full fallback cascade.

credentials and jsonl are lazily evaluated: the cascade does NOT invoke either on a fresh-cache or stale-lock-serve path, preserving the “no Keychain subprocess on cache hits” guarantee. cache and lock being None is equivalent to pointing at paths that don’t exist: reads degrade to “miss” and writes are skipped. Write failures fall into two classes. Real bugs (disk full, missing parent dir, EACCES) log via lsm_error! (bypasses the level gate). The documented Windows MoveFileEx race-loser case logs via lsm_debug! (suppressible) so multi-terminal Windows users don’t get persistent stderr noise on healthy runs. Either way the cascade still returns fetched data.