fix: local tests using pqvector fail

[ghost]

What happened?

Tests related to vector store are failing:

ERROR packages/ragbits-core/tests/integration/vector_stores/test_vector_store_sparse.py::test_vector_store_retrieve_order[PgVectorStore] - port_for.exceptions.PortForException: Can't select a port

How can we reproduce it?

uv run pytest

Relevant log output

[micpst]

Do you have PostgreSQL installed on your machine?

[micpst]

Please verify your setup with our contributing guide

[ghost]

I think I have everything set up