Pick up shutdown fix cherry-pick for v1.24.0

[yuandrew]

What was changed

Point core to https://github.com/temporalio/sdk-rust/tree/backport/poller-shutdown/5f79ef2, which has a worker shutdown fix backported via temporalio/sdk-rust#1260

Pointed the features repo in CI to pre-S3 driver sample code, since that isn't in this older version, and also set a roof for types-protobuf to match what was available during the release, since newer version is causing CI to now fail

Why?

fix shutdown

Checklist

1. Closes

2. How was this tested:

3. Any docs updates needed?

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Note

Medium Risk
Touches Rust worker shutdown plumbing in the Python bridge, which can affect runtime/thread behavior and shutdown correctness. The remaining changes are CI/dependency pinning to stabilize tests.

Overview
Fixes worker shutdown behavior in the Rust Python bridge by ensuring WorkerRef::initiate_shutdown enters the tokio runtime context (matching other sync bridge calls).

Stabilizes CI for this release line by pinning the temporalio/features workflow (and passing features-repo-ref) to a specific commit, and by adding an upper bound to types-protobuf in pyproject.toml/uv.lock to avoid newer stubs breaking older builds.

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