fix(python): clarify Boxlite context manager

[G4614]

Make native Boxlite support async context management and reject sync context-manager usage with a SyncBoxlite hint.

Test plan:

• cargo fmt --all
• sdks/python/.venv/bin/python -m py_compile sdks/python/tests/test_box_management_mock.py
• BOXLITE_DEPS_STUB=1 cargo check -p boxlite-python
• Not rerun on debug host after splitting; the same context-manager paths passed on debug host before the split in fix(python): align SDK errors and metadata #954

Summary by CodeRabbit

• New Features

  • Added async context-manager support for the Python runtime via async with.
  • Async context managers now shut down the underlying runtime automatically on exit.

• Bug Fixes

  • Using the async context manager with with now raises a clear error directing users to the correct synchronous API.
  • Attempting to use the runtime after exiting the async context now raises an informative error.

• Tests

  • Added pytest coverage for both sync-misuse and async lifecycle/shutdown behavior.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Pro Plus

Run ID: 9bd25096-9519-491f-a75f-a51f83289949

📥 Commits

Reviewing files that changed from the base of the PR and between 39cc257 and df025ad.

📒 Files selected for processing (2)

• sdks/python/src/runtime.rs
• sdks/python/tests/test_box_management_mock.py

🚧 Files skipped from review as they are similar to previous changes (2)

• sdks/python/tests/test_box_management_mock.py
• sdks/python/src/runtime.rs

---

📝 Walkthrough

Walkthrough

PyBoxlite now supports asynchronous context management, shuts down on async exit, and rejects synchronous context-manager entry with guidance to use SyncBoxlite. Tests cover both entry modes and post-shutdown behavior.

Changes

Python context management

Layer / File(s)	Summary
Context-manager hooks and validation sdks/python/src/runtime.rs, sdks/python/tests/test_box_management_mock.py	PyBoxlite implements asynchronous entry and exit hooks, rejects synchronous entry, and tests runtime shutdown and related errors.

Estimated code review effort: 2 (Simple) | ~10 minutes

Sequence Diagram(s)

sequenceDiagram
  participant PythonCaller
  participant PyBoxlite
  participant Runtime
  PythonCaller->>PyBoxlite: async with runtime
  PyBoxlite-->>PythonCaller: return runtime from __aenter__
  PythonCaller->>PyBoxlite: exit async context
  PyBoxlite->>Runtime: shutdown(None)
  PyBoxlite-->>PythonCaller: return false

Loading

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description lacks the required Summary/Changes/How to verify sections and only provides a test plan.	Rewrite it using the template headings: Summary, Changes, How to verify, and optional Risks / rollout.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately highlights the Boxlite context-manager change.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch g4614/pol-102-boxlite-context-manager

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[boxlite-agent]

📦 BoxLite review — couldn't complete

claude exited 1

stdout:
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stderr:
<empty>

_{powered by BoxLite}