Fix double-scheduling bug and Decimal CSV serialization

- Guard FocusLogger.init_focus_export_background_job with exact type
  check (type(cb) is FocusLogger) to exclude VantageLogger subclass,
  preventing duplicate hourly exports when VantageLogger is registered
  programmatically before startup
- Cast pl.Decimal columns to Float64 in FocusCsvSerializer so CSV
  output uses standard floating-point notation instead of fixed-point
  strings that Vantage's parser may reject

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

litellm/integrations/focus/focus_logger.py

@@ -137,11 +137,15 @@ class FocusLogger(CustomLogger):
     ) -> None:
         """Register the export cron/interval job with the provided scheduler."""
 
-        focus_loggers: List[
-            CustomLogger
-        ] = litellm.logging_callback_manager.get_custom_loggers_for_type(
-            callback_type=FocusLogger
-        )
+        # Use exact type match to exclude subclasses like VantageLogger,
+        # which have their own dedicated scheduling method.
+        focus_loggers: List[CustomLogger] = [
+            cb
+            for cb in litellm.logging_callback_manager.get_custom_loggers_for_type(
+                callback_type=FocusLogger
+            )
+            if type(cb) is FocusLogger
+        ]
         if not focus_loggers:
             verbose_logger.debug(
                 "No Focus export logger registered; skipping scheduler"

litellm/integrations/focus/serializers/csv.py

@@ -16,6 +16,18 @@ class FocusCsvSerializer(FocusSerializer):
 
     def serialize(self, frame: pl.DataFrame) -> bytes:
         """Encode the provided frame as a CSV payload."""
+        # Cast Decimal columns to Float64 so CSV output uses standard
+        # floating-point notation (e.g. "1.5") instead of fixed-point
+        # strings (e.g. "1.500000") that some parsers may reject.
+        decimal_cols = [
+            col
+            for col, dtype in zip(frame.columns, frame.dtypes)
+            if isinstance(dtype, pl.Decimal)
+        ]
+        if decimal_cols:
+            frame = frame.with_columns(
+                [pl.col(c).cast(pl.Float64) for c in decimal_cols]
+            )
         buffer = io.BytesIO()
         frame.write_csv(buffer)
         return buffer.getvalue()