feat(cron): add run history tracking for cron jobs

Record run_at_ms, status, duration_ms and error for each execution,
keeping the last 20 entries per job in jobs.json. Adds CronRunRecord
dataclass, get_job() lookup, and four regression tests covering
success, error, trimming and persistence.

Closes #1837

Made-with: Cursor

tests/test_cron_service.py

@@ -1,4 +1,5 @@
 import asyncio
+import json
 
 import pytest
 
@@ -32,6 +33,87 @@ def test_add_job_accepts_valid_timezone(tmp_path) -> None:
     assert job.state.next_run_at_ms is not None
 
 
+@pytest.mark.asyncio
+async def test_execute_job_records_run_history(tmp_path) -> None:
+    store_path = tmp_path / "cron" / "jobs.json"
+    service = CronService(store_path, on_job=lambda _: asyncio.sleep(0))
+    job = service.add_job(
+        name="hist",
+        schedule=CronSchedule(kind="every", every_ms=60_000),
+        message="hello",
+    )
+    await service.run_job(job.id)
+
+    loaded = service.get_job(job.id)
+    assert loaded is not None
+    assert len(loaded.state.run_history) == 1
+    rec = loaded.state.run_history[0]
+    assert rec.status == "ok"
+    assert rec.duration_ms >= 0
+    assert rec.error is None
+
+
+@pytest.mark.asyncio
+async def test_run_history_records_errors(tmp_path) -> None:
+    store_path = tmp_path / "cron" / "jobs.json"
+
+    async def fail(_):
+        raise RuntimeError("boom")
+
+    service = CronService(store_path, on_job=fail)
+    job = service.add_job(
+        name="fail",
+        schedule=CronSchedule(kind="every", every_ms=60_000),
+        message="hello",
+    )
+    await service.run_job(job.id)
+
+    loaded = service.get_job(job.id)
+    assert len(loaded.state.run_history) == 1
+    assert loaded.state.run_history[0].status == "error"
+    assert loaded.state.run_history[0].error == "boom"
+
+
+@pytest.mark.asyncio
+async def test_run_history_trimmed_to_max(tmp_path) -> None:
+    store_path = tmp_path / "cron" / "jobs.json"
+    service = CronService(store_path, on_job=lambda _: asyncio.sleep(0))
+    job = service.add_job(
+        name="trim",
+        schedule=CronSchedule(kind="every", every_ms=60_000),
+        message="hello",
+    )
+    for _ in range(25):
+        await service.run_job(job.id)
+
+    loaded = service.get_job(job.id)
+    assert len(loaded.state.run_history) == CronService._MAX_RUN_HISTORY
+
+
+@pytest.mark.asyncio
+async def test_run_history_persisted_to_disk(tmp_path) -> None:
+    store_path = tmp_path / "cron" / "jobs.json"
+    service = CronService(store_path, on_job=lambda _: asyncio.sleep(0))
+    job = service.add_job(
+        name="persist",
+        schedule=CronSchedule(kind="every", every_ms=60_000),
+        message="hello",
+    )
+    await service.run_job(job.id)
+
+    raw = json.loads(store_path.read_text())
+    history = raw["jobs"][0]["state"]["runHistory"]
+    assert len(history) == 1
+    assert history[0]["status"] == "ok"
+    assert "runAtMs" in history[0]
+    assert "durationMs" in history[0]
+
+    fresh = CronService(store_path)
+    loaded = fresh.get_job(job.id)
+    assert len(loaded.state.run_history) == 1
+    assert loaded.state.run_history[0].status == "ok"
+
+
 @pytest.mark.asyncio
 async def test_running_service_honors_external_disable(tmp_path) -> None:
     store_path = tmp_path / "cron" / "jobs.json"