fix: enforce min trigger size=1 to prevent immediate exports (#1270)

Author: mshsheikh

src/agents/tracing/processors.py

@@ -183,7 +183,7 @@ def __init__(
         self._shutdown_event = threading.Event()
 
         # The queue size threshold at which we export immediately.
-        self._export_trigger_size = int(max_queue_size * export_trigger_ratio)
+        self._export_trigger_size = max(1, int(max_queue_size * export_trigger_ratio))
 
         # Track when we next *must* perform a scheduled export
         self._next_export_time = time.time() + self._schedule_delay