Remove server implementation details from package exports

Modified `src/rendezqueue/__init__.py` to remove `RendezqueueServer`, `RendezqueueHandler`, `run_server`, `RendezqueueImpl`, and `SwapStore` from the top-level exports. Only `RendezqueueClient` is now exported, providing a cleaner public API for the client library.

These components can still be accessed via their respective submodules (e.g., `rendezqueue.server`). All tests pass with this change.

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: gendeux

src/rendezqueue/__init__.py

@@ -1,6 +1,3 @@
 from .client import RendezqueueClient
-from .server import RendezqueueServer, RendezqueueHandler, run as run_server
-from .impl import RendezqueueImpl
-from .swapstore import SwapStore
 
-__all__ = ["RendezqueueClient", "RendezqueueServer", "RendezqueueHandler", "run_server", "RendezqueueImpl", "SwapStore"]
+__all__ = ["RendezqueueClient"]