Hack to inject viper config into FlagSet bindings at startup

For Apps that already use Cobra to set a config struct or vars, and do not want to change all accesses to that config to viper.Get(), the following hack worked for me when called in a PersistentPreRun hook of the root command. Foregoes dynamic reloading though. Perhaps this could be a utility function or integrated more cleanly somehow.

// Read explicitly set values from viper and override Flags
//  values with the same long-name if they were not explicitly set
// via cmd line
func injectViper(cmdViper *viper.Viper, cmd *cobra.Command) {
	cmd.Flags().VisitAll(func(f *pflag.Flag) {
		if !f.Changed {
			if cmdViper.IsSet(f.Name) {
				cmd.Flags().Set(f.Name, cmdViper.GetString(f.Name))
			}
		}
	})```

Start with Cobra's PersistentPreRun hook and the cmd.Flags().VisitAll path shown in the issue. Review how explicitly changed flags and Viper values are expected to interact, then clarify whether the result should be a utility function or an integrated feature; done means an agreed scope and behavior, including the noted lack of dynamic reloading.