ManifestRequestInterceptor
typealias ManifestRequestInterceptor = suspend (ManifestRequest, ManifestRequestContext) -> ManifestRequestResult?
Customer hook to inspect/modify the manifest HTTP request before the SDK fetches it — invoked on the initial fetch and every poll, before the network call. Return a ManifestRequest to redirect/add headers, a ManifestMockResponse to short-circuit the network with a raw body (parsed + validated normally), or null to fetch unchanged. May suspend. If it throws, the SDK emits DA-MANIFEST-REQUEST-INTERCEPT-FAILED and falls back to the normal network fetch. Mirrors the web ManifestRequestInterceptor.