Add system alerts log with nav badge and Admin Alerts tab.

Persist job and ingestion warnings/errors for 7 days, surface a dismissible top-nav badge, treat stale OHLCV as a warning (e.g. ticker renames), and show market bar age on the ticker freshness chip.

tests/unit/test_ingestion_service.py

@@ -60,3 +60,30 @@ async def test_empty_fetch_with_existing_history_is_up_to_date(session):
 
     assert result.status == "complete"
     assert result.records_ingested == 0
+
+
+async def test_empty_fetch_with_stale_history_reports_stale(session):
+    # Provider returns nothing but last stored bar is weeks old — classic
+    # rename/delist case (e.g. SATS after it became ECHO). Must not look like success.
+    await _add_ticker(session, "SATS")
+    today = date.today()
+    old = [
+        OHLCVData(
+            ticker="SATS",
+            date=today - timedelta(days=20 + i),
+            open=100.0,
+            high=101.0,
+            low=99.0,
+            close=100.0,
+            volume=1000,
+        )
+        for i in range(3)
+    ]
+    await svc.fetch_and_ingest(session, MockMarketDataProvider(ohlcv_data=old), "SATS")
+
+    result = await svc.fetch_and_ingest(session, MockMarketDataProvider(ohlcv_data=[]), "SATS")
+
+    assert result.status == "stale"
+    assert result.records_ingested == 0
+    assert result.last_date is not None
+    assert "renamed" in (result.message or "").lower() or "halted" in (result.message or "").lower()

tests/unit/test_system_event_service.py

@@ -0,0 +1,85 @@
+"""System event log: persist, dedup, summary, acknowledge."""
+
+from __future__ import annotations
+
+import pytest
+
+from app.services import system_event_service as svc
+from tests.conftest import _test_session_factory  # type: ignore
+
+
+@pytest.fixture
+async def session():
+    async with _test_session_factory() as s:
+        yield s
+
+
+async def test_log_and_list(session):
+    row = await svc.log_event(
+        session,
+        severity="warning",
+        source="ingestion",
+        code="ohlcv_stale",
+        message="No new bars since 2026-06-23",
+        symbol="SATS",
+        dedup_key="ohlcv_stale:SATS",
+    )
+    assert row is not None
+    assert row.severity == "warning"
+
+    events = await svc.list_events(session, days=7)
+    assert len(events) == 1
+    assert events[0].symbol == "SATS"
+
+
+async def test_dedup_suppresses_repeat(session):
+    first = await svc.log_event(
+        session,
+        severity="error",
+        source="data_collector",
+        code="job_error",
+        message="boom",
+        dedup_key="job:data_collector:error",
+    )
+    second = await svc.log_event(
+        session,
+        severity="error",
+        source="data_collector",
+        code="job_error",
+        message="boom again",
+        dedup_key="job:data_collector:error",
+    )
+    assert first is not None
+    assert second is None
+    events = await svc.list_events(session, days=7)
+    assert len(events) == 1
+
+
+async def test_summary_and_acknowledge(session):
+    await svc.log_event(
+        session,
+        severity="error",
+        source="job",
+        code="job_error",
+        message="fail",
+        dedup_key="a",
+    )
+    await svc.log_event(
+        session,
+        severity="warning",
+        source="job",
+        code="job_rate_limited",
+        message="slow",
+        dedup_key="b",
+    )
+    s = await svc.summary(session, days=7)
+    assert s["total"] == 2
+    assert s["unacknowledged"] == 2
+    assert s["unacknowledged_errors"] == 1
+    assert s["unacknowledged_warnings"] == 1
+
+    n = await svc.acknowledge_all(session, days=7)
+    assert n == 2
+    s2 = await svc.summary(session, days=7)
+    assert s2["unacknowledged"] == 0
+    assert s2["total"] == 2