Skill directories may now declare prompt or watcher jobs as files (cron or one-off at).
The file is the source of truth: the scheduler re-reads every chat's jobs/ every minute,
around agent runs and before /jobs and /skills, and schedules, re-plans or removes them.
Ids are <skill>/<job>; run state lives in .volcanic/scheduler/skill-jobs-state.json, never
in jobs.json. Watchers run from the skill directory with VOLCANIC_WORKSPACE and
VOLCANIC_SKILL_DIR. Broken files are shown with the reason in /jobs, /skills, schedule list
and the new <skill_jobs> prompt section; cancel answers with the file to edit. Every part of
a skill directory is optional; file reading and frontmatter parsing move to Abstractions.