Deprecate passing a worker to PipelineRunner.run()

Register the worker with PipelineRunner.add_workers() before calling
run() instead. The worker argument still works but now emits a
DeprecationWarning and will be removed in a future release.

Update the runner docstrings, the run_test() helper, and all examples
(including the asyncio.gather() forms) to use the new pattern.

examples/multi-worker/distributed-handoff/pgmq-handoff/llm.py

@@ -175,7 +175,8 @@ async def main_async() -> None:
 
     runner = PipelineRunner(bus=bus, handle_sigint=True)
     logger.info(f"Starting {args.worker} worker, waiting for activation...")
-    await runner.run(worker)
+    await runner.add_workers(worker)
+    await runner.run()
 
 
 if __name__ == "__main__":

examples/multi-worker/distributed-handoff/pgmq-handoff/main.py

@@ -169,7 +169,8 @@ async def run_bot(transport: BaseTransport, runner_args: RunnerArguments):
         logger.info("Client disconnected")
         await worker.cancel()
 
-    await runner.run(worker)
+    await runner.add_workers(worker)
+    await runner.run()
 
 
 async def bot(runner_args: RunnerArguments):

examples/multi-worker/distributed-handoff/redis-handoff/llm.py

@@ -145,7 +145,8 @@ async def main_async() -> None:
 
     runner = PipelineRunner(bus=bus, handle_sigint=True)
     logger.info(f"Starting {args.worker} worker, waiting for activation...")
-    await runner.run(worker)
+    await runner.add_workers(worker)
+    await runner.run()
 
 
 if __name__ == "__main__":

examples/multi-worker/distributed-handoff/redis-handoff/main.py

@@ -150,7 +150,8 @@ async def run_bot(transport: BaseTransport, runner_args: RunnerArguments):
         logger.info("Client disconnected")
         await worker.cancel()
 
-    await runner.run(worker)
+    await runner.add_workers(worker)
+    await runner.run()
 
 
 async def bot(runner_args: RunnerArguments):