🧪(gentest): add testing to ci for the gentest cli

[danceratopz]

The gentest CLI currently has no test coverage - it could break at any time (perhaps due to changes in ethereum_test_rpc).

While we can see whether we can also add some unit tests for gentest, I would prioritize an end-to-end test that generates tests and then fills (and potentially consumes) them.

uv run gentest -c config.json 0xa41f343be7a150b740e5c939fa4d89f3a2850dbe21715df96b612fc20d1906be tests/paris/test_0xa41f.py
uv run fill  tests/paris/test_0xa41f.py
uv run consume direct -k test_0xa41f --evm-bin=path/to/evm-with-statetest

Few considerations for CI:

• gentest requires a full-node RPC endpoint and will require secrets in CI
• Should it be included in tox/tox_verify.yaml or have a dedicated Workflow? Perhaps add a new gentest environment in to tox.ini, but don't run it by default, it must be called via uvx --with=tox-uv tox -e gentest?