When on_job callbacks call list_jobs() (which triggers _load_store),
the in-memory state is reloaded from disk, discarding the next_run_at_ms
updates that _on_timer is actively computing. This causes jobs to
re-trigger indefinitely on the next tick.
Add an _executing flag around the job execution loop. While set,
_load_store returns the cached store instead of reloading from disk.
Includes regression test.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Keep manual runs from flipping the scheduler's running flag, rebuild merged run history records from action logs, and avoid delaying sub-second jobs to a one-second floor. Add regression coverage for disabled/manual runs, merged history persistence, and sub-second timers.
Made-with: Cursor
