Remove dead if-resp-nil checks in tagCmd and approveRoutesCmd; gRPC
returns either an error or a valid response, never (nil, nil).
Rename HasMachineOutputFlag to hasMachineOutputFlag since it has a
single internal caller in root.go.
The --namespace flag on nodes list/register and debug create-node was
never wired to the --user flag, so its value was silently ignored.
Remove it along with the deprecateNamespaceMessage constant.
Also remove the namespace/ns command aliases on users and
machine/machines aliases on nodes, which have been deprecated since
the naming changes in 0.23.0.
Set SilenceErrors and SilenceUsage on the root command so that
cobra never prints usage text for runtime errors. A SetFlagErrorFunc
callback re-enables usage output specifically for flag-parsing
errors (the kubectl pattern).
Add printError to utils.go and switch Execute() to ExecuteC() so
the returned error is formatted as JSON/YAML when --output requests
machine-readable output.
Go style recommends that log messages and error strings should not be
capitalized (unless beginning with proper nouns or acronyms) and should
not end with punctuation.
This change normalizes all zerolog .Msg() and .Msgf() calls to start
with lowercase letters, following Go conventions and making logs more
consistent across the codebase.
Extract LoadConfig from GetHeadscaleConfig, as they are conceptually
different operation, e.g.,
1) you can reload config through LoadConfig and do not get config
2) you can get config without reload config
