Currently, the Python toolchain can identify `uv` and `uv-workspace`
environments (showing the correct labels in the UI), but it fails to
activate them when opening a new terminal. This is because the
activation script resolution and command generation logic were missing
for these environment kinds.

This PR adds `uv` and `uv-workspace` to the standard virtual environment
activation flow. Since `uv` creates environments with a standard `venv`
structure, we can reuse the existing `resolve_venv_activation_scripts`
logic to find and execute the appropriate `activate` scripts for
different shells.

Release Notes:

- Fixed terminal activation for `uv` and `uv-workspace` Python
environments.