fix(tracer): capture context after first yield for improved ASGI compatibility

Author: viniciusdsmello

src/openlayer/lib/tracing/tracer.py

@@ -518,15 +518,13 @@ def __next__(self):
                                 func_kwargs=func_kwargs,
                                 context_kwarg=context_kwarg,
                             )
-                            # Capture context after trace is initialized for ASGI compatibility
-                            # This ensures we can finalize in the correct context even if
-                            # later __next__ calls happen in different worker threads
-                            self._captured_context = contextvars.copy_context()
                             self._trace_initialized = True
 
                         try:
                             chunk = next(self._original_gen)
                             self._output_chunks.append(chunk)
+                            if self._captured_context is None:
+                                self._captured_context = contextvars.copy_context()
                             return chunk
                         except StopIteration:
                             # Finalize trace when generator is exhausted