Convert the 10 commands that were still using Run with
ErrorOutput/SuccessOutput or log.Fatal/os.Exit:
- backfillNodeIPsCmd: use grpcRunE-style manual connection with
error returns; simplify the confirm/force logic
- getPolicy, setPolicy, checkPolicy: replace ErrorOutput with
fmt.Errorf returns in both the bypass-gRPC and gRPC paths
- serveCmd, configTestCmd: replace log.Fatal with error returns
- mockOidcCmd: replace log.Error+os.Exit with error return
- versionCmd, generatePrivateKeyCmd: replace SuccessOutput with
printOutput
- dumpConfigCmd: return the error instead of swallowing it
