Fix tox runner: use uv-venv-lock-runner and restore corpus downloads

The uv-venv-runner doesn't install project dependencies (it's a simple
venv creator). Switch to uv-venv-lock-runner which runs `uv sync --locked`
to install the project and all dependencies from the lockfile.

Also remove `skipsdist = true` which prevented tox from installing the
project, and use `package = skip` for the report env instead of
`skip_install`.

Author: jonathangreen

tox.ini

@@ -1,9 +1,8 @@
 [tox]
 envlist = py{312,313,314}-docker
-skipsdist = true
 
 [testenv]
-runner = uv-venv-runner
+runner = uv-venv-lock-runner
 commands_pre =
     # TODO: This can be removed once NLTK merges https://github.com/sloria/TextBlob/pull/469
     python -m nltk.downloader punkt_tab
@@ -33,8 +32,8 @@ allowlist_externals =
     pytest
 
 [testenv:report]
-runner = uv-venv-runner
-skip_install = true
+runner = uv-venv-lock-runner
+package = skip
 commands =
     coverage combine
     coverage html