- Renames test_comment_custom_author -> test_comment_ignores_caller_supplied_author
and inverts its assertion: an args['author'] override is silently
ignored; the author always comes from HERMES_PROFILE.
- Adds test_comment_schema_omits_author_override to assert the
'author' property is gone from KANBAN_COMMENT_SCHEMA so the
forgery surface stays closed if someone re-adds the schema field
by accident.
- Adds test_worker_can_comment_on_foreign_task to pin the #19713
policy decision: cross-task commenting must remain unrestricted.
Without this guard, a future change accidentally adding
_enforce_worker_task_ownership to _handle_comment would close the
documented handoff channel between tasks.