Nudge users whose lark-sheets skill predates the refactor to migrate off
the pre-refactor aliases (+read, +write, ...), without requiring anyone
to read --help.
- internal/deprecation: process-level pending Notice slot (mirrors
internal/skillscheck), surfaced in the JSON "_notice" envelope under a
"deprecated_command" key.
- internal/cmdutil: shared DeprecatedGroupID cobra group + helper so both
--help rendering and the unknown-subcommand path classify aliases the
same way.
- shortcuts/register.go: applySheetsCompatGroups splits the aliases into a
dedicated "update your skill" help group with "(-> +new)" pointers;
wrapSheetsBackwardDeprecation records the notice from Validate/Execute so
direct callers that never read --help still get flagged.
- cmd/root.go: extract composePendingNotice (now unit-testable) and split
availableSubcommandNames into current vs deprecated buckets while still
ranking unknown-subcommand suggestions across both.