[moetemp]

What changed?

This PR adds one complete, runnable example for each section of the Brook streams API proposal, in tests/contrib/streams/examples/.

Each file has the definition, the Workflow, the Activities, the Worker setup and the client code, and a module docstring that names its proposal section. README.md maps each section to its file. The Nexus examples are a later stage, so they have no file.

• ui_backend_reads.py: StreamClient.workflow_stream, subscribe with Topics and create_wait, and Record, Superseded and Closed handling.
• resume_from_offset.py: a Reader of a name= Stream that saves offset + 1 and resumes with from_offset.
• client_creates_stream.py: StreamClient.create with id, retention and auto_close, the Stream passed to a Workflow as data, and the creator's close.
• agent_publishes_turns.py: create_stream, awaited publish(*values), close_with_run, and an Activity input object that carries the Stream.
• activity_streams_tokens.py: ActivityStream with awaited publish and BufferedPublisher, and a sync Activity with SyncActivityStream.
• turn_scoped_stream.py: one Stream per turn with name= and async with, and an index Stream passed through continue-as-new.
• worker_setup.py: RedisStreamPlugin on the client, name= and default=, MemoryStreamPlugin for tests, and create_stream_nowait and publish_nowait in @workflow.init.

Why?

Moe asked for full examples that match the proposal. Running them in CI keeps them from going stale.

How did you test it?

test_examples.py runs each example end to end on the memory Store and on a scratch redis-server, against the stock dev server. pytest tests/contrib/streams and poe lint pass.

• Unit Tests
• Staging
• End to End Tests

[moetemp]

Closing as stale. This layer is folded into the v5 tip, #365, and the upstream review uses a fresh series instead. Plan: https://www.notion.so/4048fc567738814990b7c796ac28fe3f