First scratch workspace creation on an install now emits a one-shot
warning log + a 'tip_scratch_workspace' event on the task. Sentinel
file at ~/.hermes/kanban/.scratch_tip_shown silences subsequent
creations across the whole install.
Behavior unchanged — scratch is still ephemeral by design. This just
makes the design visible to new users (reported in user community:
'progress files vanished, no warning anywhere').
Docs (en + ko) updated to spell out 'Deleted when the task completes'
on the scratch bullet and 'Preserved on completion' on worktree/dir.
Salvages #21823 by @pochi-gio. Adds Korean (ko) Docusaurus locale and
translates Kanban documentation (kanban.md, kanban-tutorial.md) and the
two related skills (devops-kanban-orchestrator, devops-kanban-worker).
Purely additive — adds ko to the locales list in docusaurus.config.ts
and creates the website/i18n/ko/ tree.