fix: cast usage run filter JSON values to Float instead of Integer (#574)

The duration and tokenUsage numberRange filters cast the JSON text value
to INTEGER, but some rows store call_duration_seconds as a JSON float
(0.0, written by get_call_duration when the pipeline never recorded a
start time). Postgres cannot cast the text '0.0' to integer, so any
duration filter on /organizations/usage/runs failed with
InvalidTextRepresentationError. Cast to FLOAT instead, matching the
duration sort clause, and make get_call_duration return an int so new
rows are written as integers.

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>

api/services/pipecat/pipeline_metrics_aggregator.py

@@ -113,10 +113,10 @@ class PipelineMetricsAggregator(FrameProcessor):
         """Get the aggregated STT usage metrics grouped by processor|||model."""
         return self._stt_usage_metrics
 
-    def get_call_duration(self) -> float:
+    def get_call_duration(self) -> int:
         """Get call duration"""
         if self._start_time is None:
-            return 0.0
+            return 0
 
         if self._stop_time is None:
             call_duration = time.time() - self._start_time