feat(contracts,db): scheduled_job registry tables and schedules API contracts
- 0028_scheduled_jobs: scheduled_job (stable key, group, kind task|agent_check,
enabled/schedule with defaults + customized flag, config, last_* / next_run_at /
run_requested_at / running_since, counters) and scheduled_job_run history
- contracts/schedules.ts: ScheduleSpec (interval | 5-field cron), AgentCheckConfig
(goal template, capability allowlist, budget, trigger condition, allowRecover,
reportAsDecision), board / run views
- Api.schedules: list, create (agent_check only), update, remove, run-now, skip,
runs; all admin + console session only
Co-Authored-By: Claude Opus 5.5 <[email protected]>