This PR fixes a bug where setting AutoTokenRefresh: false in Config had no effect because setDefaults would unconditionally overwrite a false bool field with its struct-tag default (true). The fix converts AutoTokenRefresh to *bool, where nil means "enabled" (preserving existing behavior for callers who omit the field) and a pointer to false genuinely disables the background refresh.

• The root-cause code — the reflect.Bool case in setDefaults — is cleanly removed along with the now-redundant struct tags on both AutoTokenRefresh and SilentMode.
• All three call sites (NewInfisicalClient, UpdateConfiguration, and handleTokenLifeCycle) are updated to use the new autoTokenRefreshEnabled helper.
• This is a breaking API change for any callers that currently set AutoTokenRefresh explicitly; they must switch to pointer syntax.

1. client.go, line 504-507 (link)

   Goroutine keeps idling after AutoTokenRefresh is disabled at runtime

   When a client is created with AutoTokenRefresh enabled (nil or &true), the goroutine is started unconditionally. If UpdateConfiguration is later called with AutoTokenRefresh: Bool(false), the goroutine falls into the else branch and loops indefinitely on a 1-second sleep — it can only be terminated by cancelling the original context. This is now a reachable path (the old default-override bug prevented it), so callers who call UpdateConfiguration to turn off auto-refresh expecting the background worker to stop will be surprised. At minimum the comment on this branch should note that the goroutine stays alive until context cancellation.