Use workflow init from samples

[drewhoskins-temporal]

What was changed

Workflow Init is a brand new feature.
Let's show people best practices for each sample that uses a signal or update handler and receives workflow arguments.

Why?

These changes make sure these workflows are initialized before signal or update handlers are run.

Checklist

1. Closes

2. How was this tested:

Automated:
poetry run pytest workflow_test.py
Manual:
Follow instructions in
bedrock/entity/README.md
and
message_passing/safe_message_handlers/README.md

3. Any docs updates needed?

[cretz]

LGTM, holding approval until tagged release of SDK is made

[brianstrauch]

Status update: I've brought this branch up to date with main (merge, no force-push, so the original commits are intact).

Most of this PR landed through other paths while it sat, so the diff is now a single file.

Already on main:

• message_passing/safe_message_handlers/workflow.py — Cluster manager: use update to wait for cluster to start #153 ("Use workflow.init, refactor") made the same change in Dec 2024: same decorator, same def init(self, input) method removed, same lines moved into the constructor.
• message_passing/introduction/workflows.py — the comment this PR fixed (See GreetingWorkflowWithAsyncHandler below) was deleted entirely by Improve/fix comments explaining message passing introduction sample #148, so there's nothing left to correct.

Dropped:

• poetry.lock — deleted from the repo in Migrate to uv #170 (migrate to uv).
• pyproject.toml — this was only the temporary temporalio = { path = "../sdk-python" } local-path dep, which was never meant to merge.

Remaining: @workflow.init on EntityBedrockWorkflow (bedrock/entity/workflows.py, +10/-6). It takes workflow arguments and has signal handlers that mutate the same state those arguments initialize, so it's a good fit for the pattern.

Verified with ruff, mypy, and an end-to-end run against the time-skipping test environment with a stubbed Bedrock activity, sending a signal alongside a pre-populated prompt_queue to confirm the constructor's params are applied before the signal is handled. Note there are no automated tests covering the bedrock samples, so that check was manual.

Note the PR description above is now stale — it describes the broader multi-sample scope and references poetry run pytest.