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.

app/services/ingestion_service.py

@@ -59,6 +59,19 @@ async def _get_ohlcv_bar_count(db: AsyncSession, ticker_id: int) -> int:
     return int(result.scalar() or 0)
 
 
+async def _get_latest_ohlcv_date(db: AsyncSession, ticker_id: int) -> date | None:
+    result = await db.execute(
+        select(func.max(OHLCVRecord.date)).where(OHLCVRecord.ticker_id == ticker_id)
+    )
+    return result.scalar_one_or_none()
+
+
+# If the provider returns no bars but our last stored session is older than this,
+# treat the run as stale (not "success / up to date"). Common causes: ticker
+# rename, delisting, or multi-day halt — SATS→ECHO is the canonical example.
+_STALE_OHLCV_GAP_DAYS = 5
+
+
 async def _update_progress(
     db: AsyncSession, ticker_id: int, last_date: date
 ) -> None:
@@ -145,8 +158,9 @@ async def fetch_and_ingest(
 
     # Provider returned nothing. With no history at all this almost always means
     # the provider doesn't cover this symbol (Alpaca = US listings only) — surface
-    # that instead of a misleading "success". With existing bars it just means
-    # there were no new bars in the requested window.
+    # that instead of a misleading "success". With recent history, an empty window
+    # usually means weekends/holidays. With a multi-day gap, the symbol is likely
+    # halted, delisted, or *renamed* (e.g. SATS → ECHO) and we must not claim success.
     if not records:
         existing = await _get_ohlcv_bar_count(db, ticker.id)
         if existing == 0:
@@ -160,10 +174,24 @@ async def fetch_and_ingest(
                     "(Alpaca serves US-listed securities only)."
                 ),
             )
+        latest = await _get_latest_ohlcv_date(db, ticker.id)
+        gap_days = (end_date - latest).days if latest is not None else None
+        if gap_days is not None and gap_days > _STALE_OHLCV_GAP_DAYS:
+            return IngestionResult(
+                symbol=ticker.symbol,
+                records_ingested=0,
+                last_date=latest,
+                status="stale",
+                message=(
+                    f"No new bars since {latest.isoformat()} ({gap_days}d gap). "
+                    "The symbol may be halted, delisted, or renamed under a new ticker — "
+                    "check the listing and add/fetch the current symbol if it changed."
+                ),
+            )
         return IngestionResult(
             symbol=ticker.symbol,
             records_ingested=0,
-            last_date=None,
+            last_date=latest,
             status="complete",
             message="Already up to date — no new bars.",
         )