fix: harden Structural S/R after OHLCV writes and surface cleanup failures

Honor custom S/R tolerance as a transient detect, refresh levels after OHLCV
mutations without failing committed price writes, report per-ticker S/R
rebuild failures from admin cleanup, and warn in the admin UI when refresh is partial.

app/routers/sr_levels.py

@@ -74,7 +74,11 @@ async def read_sr_levels(
         None,
         ge=0,
         le=0.1,
-        description="Merge tolerance as fraction of price; omit for ATR-adaptive default",
+        description=(
+            "Merge tolerance as fraction of price. Omit to return persisted levels "
+            "(ATR-adaptive at last recalculation). When set, returns a transient "
+            "detect with this tolerance (not written to the DB)."
+        ),
     ),
     max_zones: int = Query(6, ge=0, description="Max S/R zones to return (default 6)"),
     _user=Depends(require_access),