Export Context Propagate APIs through Logfire Interface

[dhruv-ahuja]

This PR addresses feedback provided in the issue #1324 by exporting propagate.py's get_context and attach_context APIs through the Logfire module interface.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

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[alexmojaki]

Thanks! Please also update docs where possible, e.g. https://logfire.pydantic.dev/docs/how-to-guides/distributed-tracing/#manual-context-propagation. The old usage is still correct but it'd be nice to show the new simpler usage.

[dhruv-ahuja]

@alexmojaki I have cross-checked and ensured all code examples and documentation is using import logfire everywhere.
Please check now and let me know if anything else is needed.

Also once done, please let me know what issue I can pick up next.

[alexmojaki]

Thanks! If you'd like to do more take a look at https://github.com/pydantic/logfire/issues?q=is%3Aissue%20state%3Aopen%20label%3A%22good%20first%20issue%22