fix(runtime): guard sync API inside async contexts (#1085)

[samojavo]

Guard sync API when called from async contexts.

• If called on the CocoIndex-managed loop: raise RuntimeError (prevents deadlock).
• If called on a different running loop: emit a warning and run safely.
• If no loop is running: run as usual.

Closes #1085.

[georgeh0]

Thanks for the PR! Code change looks pretty good! Please fix the CI check failure.

[georgeh0]

A check failed. Looks like it's because this type annotation is removed. You may try to bring it back and locally run dmypy run python to see if the type checking passes.

[georgeh0]

Format check failed. You may follow the guide here to do pre-commit install and run it locally. Thanks!

[samojavo]

i did run ruff format so it should be fine now

[georgeh0]

Thanks for making this!