[REA-6846] Release 3.7.0 with data-channel chunking and step sessions

[douglaseel]

Why

Releases what has landed since 3.6.1. It adds new public surface and moves nothing on the wire, which makes it a minor release:

• Data-channel chunking ([REA-6846] Answer data-channel chunking with reactor-webrtc 0.19 #228–[REA-6846] Send what a chunked channel queues before closing it #230). WebRtcConfig.dc_chunking is on by default. The runtime answers clients that ask for chunked data channels, so a command or a model message of up to 64 MiB passes, instead of being capped at 256 KiB. Refused frames are logged once per channel, and a teardown sends what a chunked channel still has queued. A client that doesn't ask keeps the plain channel.
• Step sessions ([REA-6854] Deliver commands and reactor events to the model in posted order #231–[REA-6855] Serve saved step folders over HTTP #239): a session's starting input and step count on the start body, complete_step(), closing a session at its steps, the runtime.step_results manifest block, and step output saved as an MP4 or a folder of files, served over HTTP.
• Client stats ([REA-6588] Decode client-observed WebRTC stats in the transport and hand them to the runner #201, [REA-6696] Journal client stats as metric self-loops #224): client-observed WebRTC stats decoded in the transport and journaled as metric self-loops.
• reactor-webrtc 0.21.0 (from 0.19.1).
  • 0.21.0 keeps per-frame metadata on its own frame when libwebrtc drops a frame before render. Before, metadata was matched by queue order, so after a dropped frame every later frame got its predecessor's metadata.
  • It also keeps a FrameTransform's replace_data through the metadata step.
  • 0.20.0 is additive.
  • Neither changes the Python API the runtime uses.
• Dependency bumps (Bump actions/checkout from 6 to 7 #216–Bump uvicorn from 0.52.1 to 0.54.0 #220).

What Changed

Two commits:

• uv version 3.7.0, which updates the version in pyproject.toml and uv.lock;
• reactor-webrtc==0.21.0, relocked. Only that package moves in uv.lock.

Merging tags v3.7.0 and publishes.

Checked locally with a locked install of the published reactor-webrtc 0.21.0 wheel:

• lint, typecheck and the HTTP spec check pass;
• unit tests pass (1917);
• integration tests pass (12).

And with the release workflow's own gates:

• mise run http-breaking-release: "3.6.1 -> 3.7.0 (minor) satisfies the mandated patch";
• mise run wire-check-release: the pin matches proto/;
• mise run build: builds the 3.7.0 wheel and sdist.

🤖 Generated with Claude Code

[douglaseel]

• [REA-6846] Release 3.7.0 with data-channel chunking and step sessions #240 👈 (View in Graphite)
• main

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[github-actions]

[codex-review] Codex review running. Scope: full (0a1e19a..095f0b0).

[douglaseel]

Merge activity

• Oct 5, 11:21 PM UTC: A user started a stack merge that includes this pull request via Graphite.
• Oct 5, 11:21 PM UTC: @douglaseel merged this pull request with Graphite.