Wraps fetch with retry-on-transient-failure and throws FetchError on
non-2xx. Retries on HTTP 5xx, HTTP 429, and TypeError (network errors
like "Failed to fetch"); returns immediately on other 4xx so typo'd URLs
fail fast. AbortError and other exceptions propagate untouched.
Wraps
fetchwith retry-on-transient-failure and throwsFetchErroron non-2xx. Retries on HTTP 5xx, HTTP 429, andTypeError(network errors like "Failed to fetch"); returns immediately on other 4xx so typo'd URLs fail fast. AbortError and other exceptions propagate untouched.Exponential backoff: 200ms, 600ms; ~800ms worst-case added latency.